Here is a sixth beta test for Teensyduino 1.60

Paul · Jan 17, 2026

Here is a sixth beta test for Teensyduino 1.60.

This is meant to be a release candidate. My hope is to release 1.60 with
the many small fixes that accumulated since 1.59 before starting major new
development.

Arduino 2.3.x, all systems:

https://www.pjrc.com/teensy/td_160-beta6/package_teensy_0.60.6_index.json

1: Quit Teensy Loader, if running
2: Use Boards Manager to uninstall Teensy, if previously installed
3: Use File > Preferences (Arduino IDE > Settings on MacOS) to install new URL
4: Press Ctrl-Shift-P (Command-Shift-P on MacOS) click "Arduino: Update Indexes"
5: Use Boards Manager to install Teensy
6: Restart Arduino IDE (if using plugin for Lockable Teensy)

Arduino 1.8.x, Linux 64 bit:

https://www.pjrc.com/teensy/td_160-beta6/TeensyduinoInstall.linux64

Arduino 1.8.x, Linux ARM:

https://www.pjrc.com/teensy/td_160-beta6/TeensyduinoInstall.linuxarm

Arduino 1.8.x, Linux ARM64:

https://www.pjrc.com/teensy/td_160-beta6/TeensyduinoInstall.linuxaarch64

Arduino 1.8.x, Windows:

https://www.pjrc.com/teensy/td_160-beta6/TeensyduinoInstall.exe

PlatformIO, DIY beta support:

https://forum.pjrc.com/threads/71730

Changes since Teensyduino 1.60-beta5:

Wire: Use glitch filter in slave mode
Wire: Fix slave mode onReceive() for repeat start
USB Keyboard define GUI key names
USB MIDI receive return channel=0 for system messages
USB MTP improve ability to use in custom USB device
USBHost_t36: recover from device errors during enumeration

h4yn0nnym0u5e · Jan 17, 2026

Paul said:
USB MTP improve ability to use in custom USB device

This covers some, but not all, of the changes I put in PR #790.

KurtE · Jan 17, 2026

Paul said:
https://www.pjrc.com/teensy/td_160-beta6/package_teensy_0.60.6_index.json

Wondering at some point if it would make sense to have just two different json files
1) for Released versions only
2) for Beta (and released?) versions

KurtE · Jan 17, 2026

Wish list item:

I wish I could build Teensy sketches that use MTP or USBHost, when I have the official version of SDFat installed. For example, the HIDDeviceInfo sketch that I was running again yesterday to remind myself how the N-Key rollover keyboard support worked.
And it errored out:

Code:

"C:\\Users\\kurte\\AppData\\Local\\Arduino15\\packages\\teensy\\tools\\teensy-compile\\11.3.1/arm/bin/arm-none-eabi-g++" -c -O2 -g -Wall -ffunction-sections -fdata-sections -nostdlib -MMD -std=gnu++17 -fno-exceptions -fpermissive -fno-rtti -fno-threadsafe-statics -felide-constructors -Wno-error=narrowing -Wno-psabi -mthumb -mcpu=cortex-m7 -mfloat-abi=hard -mfpu=fpv5-d16 -D__IMXRT1062__ -DTEENSYDUINO=160 -DARDUINO=10607 -DARDUINO_TEENSY_MICROMOD -DF_CPU=600000000 -DUSB_SERIAL -DLAYOUT_US_ENGLISH "-IC:\\Users\\kurte\\AppData\\Local\\arduino\\sketches\\6B7CB48BAE9F173DBFD6C9074088CF56/pch" "-IC:\\Users\\kurte\\AppData\\Local\\Arduino15\\packages\\teensy\\hardware\\avr\\0.60.6\\cores\\teensy4" "-IC:\\Users\\kurte\\AppData\\Local\\Arduino15\\packages\\teensy\\hardware\\avr\\0.60.6\\libraries\\USBHost_t36" "-Ic:\\Users\\kurte\\Documents\\Arduino\\libraries\\SdFat\\src" "-IC:\\Users\\kurte\\AppData\\Local\\Arduino15\\packages\\teensy\\hardware\\avr\\0.60.6\\libraries\\SPI" "-IC:\\Users\\kurte\\AppData\\Local\\Arduino15\\packages\\teensy\\hardware\\avr\\0.60.6\\libraries\\EEPROM" "C:\\Users\\kurte\\AppData\\Local\\arduino\\sketches\\6B7CB48BAE9F173DBFD6C9074088CF56\\sketch\\HIDDeviceInfo.ino.cpp" -o "C:\\Users\\kurte\\AppData\\Local\\arduino\\sketches\\6B7CB48BAE9F173DBFD6C9074088CF56\\sketch\\HIDDeviceInfo.ino.cpp.o"
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:461:2: warning: #warning File not defined because __has_include(FS.h) [-Wcpp]
  461 | #warning File not defined because __has_include(FS.h)
      |  ^~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In constructor 'MSCFile::MSCFile(const FsFile&)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2691:35: error: use of deleted function 'FsFile::FsFile(const FsFile&)'
 2691 |     MSCFile(const FsFile &file) : mscfatfile(file), filename(nullptr) { }
      |                                   ^~~~~~~~~~~~~~~~
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: note: 'FsFile::FsFile(const FsFile&)' is implicitly deleted because the default definition would be ill-formed:
  905 | class FsFile : public StreamFile<FsBaseFile, uint64_t> {
      |       ^~~~~~
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: error: use of deleted function 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)'
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatFile.h:882,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatVolume.h:27,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatLib.h:28,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:30,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: note: 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)' is implicitly deleted because the default definition would be ill-formed:
   76 | class StreamFile : public stream_t, public BaseFile {
      |       ^~~~~~~~~~
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: error: 'FsBaseFile::FsBaseFile(const FsBaseFile&)' is private within this context
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:75:3: note: declared private here
   75 |   FsBaseFile(const FsBaseFile& from);
      |   ^~~~~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\USBDeviceInfo.cpp:27:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In member function 'virtual bool USBFilesystem::getVolumeLabel(char*, size_t)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2816:79: error: 'class FsVolume' has no member named 'getVolumeLabel'
 2816 |     virtual bool getVolumeLabel(char *volume_label, size_t cb) { return mscfs.getVolumeLabel(volume_label, cb); }
      |                                                                               ^~~~~~~~~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:461:2: warning: #warning File not defined because __has_include(FS.h) [-Wcpp]
  461 | #warning File not defined because __has_include(FS.h)
      |  ^~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In constructor 'MSCFile::MSCFile(const FsFile&)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2691:35: error: use of deleted function 'FsFile::FsFile(const FsFile&)'
 2691 |     MSCFile(const FsFile &file) : mscfatfile(file), filename(nullptr) { }
      |                                   ^~~~~~~~~~~~~~~~
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: note: 'FsFile::FsFile(const FsFile&)' is implicitly deleted because the default definition would be ill-formed:
  905 | class FsFile : public StreamFile<FsBaseFile, uint64_t> {
      |       ^~~~~~
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: error: use of deleted function 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)'
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatFile.h:882,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatVolume.h:27,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatLib.h:28,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:30,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: note: 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)' is implicitly deleted because the default definition would be ill-formed:
   76 | class StreamFile : public stream_t, public BaseFile {
      |       ^~~~~~~~~~
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: error: 'FsBaseFile::FsBaseFile(const FsBaseFile&)' is private within this context
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:75:3: note: declared private here
   75 |   FsBaseFile(const FsBaseFile& from);
      |   ^~~~~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDeviceInfo.ino:27:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In member function 'virtual bool USBFilesystem::getVolumeLabel(char*, size_t)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2816:79: error: 'class FsVolume' has no member named 'getVolumeLabel'
 2816 |     virtual bool getVolumeLabel(char *volume_label, size_t cb) { return mscfs.getVolumeLabel(volume_label, cb); }
      |                                                                               ^~~~~~~~~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:461:2: warning: #warning File not defined because __has_include(FS.h) [-Wcpp]
  461 | #warning File not defined because __has_include(FS.h)
      |  ^~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In constructor 'MSCFile::MSCFile(const FsFile&)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2691:35: error: use of deleted function 'FsFile::FsFile(const FsFile&)'
 2691 |     MSCFile(const FsFile &file) : mscfatfile(file), filename(nullptr) { }
      |                                   ^~~~~~~~~~~~~~~~
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: note: 'FsFile::FsFile(const FsFile&)' is implicitly deleted because the default definition would be ill-formed:
  905 | class FsFile : public StreamFile<FsBaseFile, uint64_t> {
      |       ^~~~~~
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:905:7: error: use of deleted function 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)'
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatFile.h:882,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatVolume.h:27,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/ExFatLib/ExFatLib.h:28,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:30,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: note: 'StreamFile<FsBaseFile, long long unsigned int>::StreamFile(const StreamFile<FsBaseFile, long long unsigned int>&)' is implicitly deleted because the default definition would be ill-formed:
   76 | class StreamFile : public stream_t, public BaseFile {
      |       ^~~~~~~~~~
c:\users\kurte\documents\arduino\libraries\sdfat\src\common\arduinofiles.h:76:7: error: 'FsBaseFile::FsBaseFile(const FsBaseFile&)' is private within this context
In file included from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsLib.h:31,
                 from c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/SdFat.h:32,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2451,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
c:\Users\kurte\Documents\Arduino\libraries\SdFat\src/FsLib/FsFile.h:75:3: note: declared private here
   75 |   FsBaseFile(const FsBaseFile& from);
      |   ^~~~~~~~~~
In file included from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.h:4,
                 from C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36\examples\HIDDeviceInfo\HIDDumper.cpp:23:
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h: In member function 'virtual bool USBFilesystem::getVolumeLabel(char*, size_t)':
C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36/USBHost_t36.h:2816:79: error: 'class FsVolume' has no member named 'getVolumeLabel'
 2816 |     virtual bool getVolumeLabel(char *volume_label, size_t cb) { return mscfs.getVolumeLabel(volume_label, cb); }
      |                                                                               ^~~~~~~~~~~~~~
Multiple libraries were found for "SdFat.h"
  Used: C:\Users\kurte\Documents\Arduino\libraries\SdFat
  Not used: C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\SdFat
Using library USBHost_t36 at version 0.2 in folder: C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\USBHost_t36
Using library SdFat at version 2.3.0 in folder: C:\Users\kurte\Documents\Arduino\libraries\SdFat
Using library SPI at version 1.0 in folder: C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\SPI
Using library EEPROM at version 2.0 in folder: C:\Users\kurte\AppData\Local\Arduino15\packages\teensy\hardware\avr\0.60.6\libraries\EEPROM
exit status 1

Compilation error: exit status 1

Possible solutions:
a) build the Teensy boards with their own Arduino Architecture and mark the Teensy version with this... Yea I know very unlikely this approach
will be taken.

b) Rename the Teensy version of this library to something else. Could cause issues with Teensy sketches that directly include "SDFat.h"

c) Do a hack like I tried in a different Beta here (and lost when new beta installed), which works something like:

Add a new header file to your SDFat version, like: "TeensySDFat.h", which simply includes "SDFat.h", change

Change "SD.h" to include: TeensySDFat.h instead of SDFat.h (optionly within has_include stuff

Similar change to USBHost_t36.h - Note it include SDFat.h and not SD.h? Maybe it should?

MTP - I think will be resolved by change in SD.h

mjs513 · Jan 17, 2026

This one that @KurtE mention is on my wish list as well

KurtE said:
c) Do a hack like I tried in a different Beta here (and lost when new beta installed), which works something like:

Add a new header file to your SDFat version, like: "TeensySDFat.h", which simply includes "SDFat.h", changeChange "SD.h" to include: TeensySDFat.h instead of SDFat.h (optionly within has_include stuffSimilar change to USBHost_t36.h - Note it include SDFat.h and not SD.h? Maybe it should?MTP - I think will be resolved by change in SD.h

shawn · Jan 17, 2026

I updated the PlatformIO beta links: https://forum.pjrc.com/index.php?th...-beta-release-to-platformio.71730/post-364847

PaulStoffregen · Jan 17, 2026

Questions for everyone using Windows, even if not using old Arduino, does your browser let you download the installer and does Windows let you run it and does it says publisher is known to be PJRC? No need to actually use the installer, just getting to the intro page is enough to tell if we're past these issues with signing.

defragster · Jan 17, 2026

PaulStoffregen said:
using Windows,

Had to override EXE to KEEP the download and now it needed to be Unblocked to run:

Works fine to install and build after that

KenHahn · Jan 17, 2026

Windows 11 with Chrome. Installed 1.8.x version. Had to give usual permission to go ahead and install to get past Defender. Sees PJRC as publisher

h4yn0nnym0u5e · Jan 17, 2026

With Windows 10 x64 I got:

"More info" gives (note I renamed it as I was downloading it)

"Run anyway" gave me a dialogue box I couldn't screenshot - "Do you want to allow this app to make changes?"
"Yes" finally got to the installer:

EDIT: this was also with Chrome - no issues with downloading it

defragster · Jan 17, 2026

Download here was marked 'NO' as usual and had to 'Keep' anyway.
That maybe EDGE security feature, Never use chr0me - systems are safer uninstalling it ... which I have one here to do that on just now.

As shown in p#8 - marking 'Unblock' in properties allows it to then run without the Defender Windows Security blocking popup showing as in p#9 and #10.

kd5rxt-mark · Jan 17, 2026

Running Windows 11 Pro Version 25H2 (OS build 26200.7263) on my HP Small Footprint workstation (I'll install on my main ASUS gaming laptop tomorrow & report those results separately). Got warnings that are visually the same as reported by @h4yn0nnym0u5e in p#10, then initially reported suspicious by Norton360, but eventually passed their scan without my intervention, & was allowed to proceed as a valid install.

Mark J Culross
KD5RXT

joepasquariello · Jan 17, 2026

Installed 1.60b6 on Windows 10. After installing 1.8.19, got "Do not run" warning when I ran the TeensyDuino installer. Told it to run anyway, and everything installed fine. Built some of my larger projects without problems, but haven't run any yet.

mjs513 · Jan 18, 2026

Morning all
Just tried it on win11 ide 1.8.19 and after getting the nonsense of not typically downloaded looked at file properties and saw the signature

WMXZ · Jan 18, 2026

Cannot contribute, Windows11 pro here, Arduino2.3.6, No issues what so ever. OK, I did not download the exefile but used the boards manager.

CollinK · Jan 18, 2026

Awesome! I've been using 1.59 with platformio because I'm loathe to use the beta. Funny enough, I forget why anymore. But, I ended up not using the beta any longer and so I stick with 1.59. It'll be awesome to have 1.60 be officially released... some day. At any rate, I'm excited to see progress on this.

Nantonos · Jan 21, 2026

Windows 11 Home, as others reported I get the "Windows protected your PC" and you have to click "more info" to see that PJRC signed it and to get the option to "run anyway".

Nantonos · Jan 21, 2026

Win 11 Home, no problems installing and compiling with the board manager, using Arduino 2.3.7

kd5rxt-mark · Jan 21, 2026

Running Windows 11 Pro Version 25H2 (OS build 26200.7263) on my main ASUS gaming laptop (12th Gen Intel(R) Core(TM) i7-12700H (2.30 GHz) w/ 64GM RAM). Got same warnings as reported for my HP Small Footprint Workstation, then again, initially reported suspicious by Norton360, but eventually passed their scan without my intervention, & was allowed to proceed as a valid install. Then when building, several components were initially reported as suspicious by Norton360, but all eventually passed all of their scans & the builds completed successfully.

A couple of my more complicated source files (Teensy-MIDI-RA8876-PolySynth-Display for T4.1 in MIDI+Serial, with FASTER optimization, at the default speed of 600MHz & Teensy-MIDI-RA8875-PolySynth-Audio for T4.0 in Serial + MIDI + Audio, with SMALLEST CODE WITH LTO optimization, overclocked to 816MHz) both built with no problems.

Mark J Culross
KD5RXT

PaulStoffregen · Jan 21, 2026

Has anyone used this beta on MacOS yet?

shawn · Jan 21, 2026

PaulStoffregen said:
Has anyone used this beta on MacOS yet?

Yes, and with GCC 14.2.1 and C++20. Via PlatformIO.

shawn · Jan 21, 2026

shawn said:
Yes, and with GCC 14.2.1 and C++20. Via PlatformIO.

It seems to be running fine in a commercial project running LED panels with sACN and Art-Net. Pretty solid thus far.

KurtE · Jan 22, 2026

I should have mentioned that on Windows 11, Norton again complained about several of the teensy apps.
With Teensy.exe it was going to quarantine it which I overrode. Some of the others it complained about was
teensy_size, teensy_after... Which it analyzed for a bit and came back and said they were OK...

PaulStoffregen · Jan 31, 2026

KurtE said:
I wish I could build Teensy sketches that use MTP or USBHost, when I have the official version of SDFat installed.

I should have commented about this earlier. Probably no surprise that I'm going to leave the currently customized SdFat as-is for 1.60. Changing something that could have unintended consequences so soon before a release seems too risky.

Something that probably will come as a surprise is that I've been fiddling with hardware mods to possibly support UHS in future Teensy. I actually have a first try at the hardware on my workbench right now, and a PCB is on order with OSH Park to work around some thorny issues that can come up after the switch to 1.8V signals.

I can't give any sort of timeline when this work will mature into a beta test and eventual product release. In fact, just saying this much is probably going a bit too far. But I can tell you as part of this work I will soon be diving into SdFat low-level code again. When I do, I'll keep this conflict with Bill's original SdFat in mind. I'm sure there's a good way to solve it.

KurtE · Feb 1, 2026

PaulStoffregen said:
I should have commented about this earlier. Probably no surprise that I'm going to leave the currently customized SdFat as-is for 1.60. Changing something that could have unintended consequences so soon before a release seems too risky.

Understand, although personally I do wish we at least had a simple partial solution, like, simply adding a file to your version of SDFat, like:
PaulStoffregens_SDFat.h or PJRC_ or Teensy_ something that probably does not exist elsewhere, and it simply includes SDFat.h.
And then change SD library to include it instead of SDFat. It is not perfect but probably hits the 80-90% case...

But I understand your desire to get this next release out as it has been more or less a year since the last release. So fill keep fingers crossed with the UHS work, that it will be addressed then!

Here is a sixth beta test for Teensyduino 1.60

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