Download error and now 2 bricked Teensies

[cageycruz]

I have a Teensy 3.2 and wanted to try it out for the first time. Got the code to blink the LED and made 2 changes in the delay values to make a distinctly different blink pattern. I plugged in the Teensy, it started blinking. Opened up Teensyduino, set the board to "Teensy 3.2/3.1", put in the code, clicked the arrow to compile and download. Teensy Loader came up with a picture saying to press the button. I did that and the picture changed to show the Teensy and a progress message about downloading. But then "Download Error." I unplugged it.

Now the board appears bricked. It no longer blinks at all when I plug it in. It does not show up in the System Report of connected USB devices. Teensy Loader no longer displays the picture saying to press the button. Trying to download the sketch again and Loader just says "Erasing" then "Download Error." Clicking Reboot gives "Unable to reboot."

Thinking I might have a bad board I foolishly tried it again. Same sketch, same procedure but this time with a Teensy LC. Got the same result, another apparently bricked board. I've tried this a few times with each board but the same results.

I'm using Teensyduino 1.53 (Arduino 1.8.13) and Teensy Loader 1.53.
Macintosh MacBook Pro Touchbar. Mac OS 11.4.
Connecting with a powered USB hub that plugs into USB C on the Mac and has several USB type A jacks.
No power supply or other hardware connected.

I've tried holding the button for 15 sec at power on but that didn't seem to do anything.

Here's the code:

/*
  Blink

  Turns an LED on for one second, then off for one second, repeatedly.

  Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
  it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
  the correct LED pin independent of which board is used.
  If you want to know what pin the on-board LED is connected to on your Arduino
  model, check the Technical Specs of your board at:
  https://www.arduino.cc/en/Main/Products

  modified 8 May 2014
  by Scott Fitzgerald
  modified 2 Sep 2016
  by Arturo Guadalupi
  modified 8 Sep 2016
  by Colby Newman

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/Blink
*/

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(100);                       // wait for 0.1 second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(3000);                       // wait for 3 seconds
}

[defragster]

T_LC and T_3.2 do not have any 15 Sec Restore feature, they are simpler MCU's without extra complexity the 3.5, 3.6 , 4.0 , and 4.1 introduced.

Perhaps Close the IDE
Close Teensy Loader
Unplug all the Teensys
Pick one or the other to test first
Do a Verify Build for that board of a simple blink
That should open TeensyLoader
In TeensyLoader under Help open Verbose
Then holding the Button plug in that first Teensy - wait a second holding the button - then release the button?

Does it program normally? If not Save the Verbose log and upload that file on the Go Advanced post option for file upload.

Unplug that Teeny
Change the IDE selected board to the other
Clear the TeensyLoader log
Do a Verify build of the sketch
Then holding the Button plug in that first Teensy - wait a second holding the button - then release the button?

Does it program normally? If not Save the Verbose log and upload that file on the Go Advanced post option for file upload.

[cageycruz]

@defragster

Thanks for the suggestion. I did all the steps you mentioned.
Unfortunately neither board programmed normally. I did get the Verbose log files. Hopefully that can help.

[cageycruz]

Bumping this up hoping someone has an answer. I’d really like to use a teensey for a project but since I can’t even program Blink I’m at a loss what to try.

[PaulStoffregen]

Try a different computer.

Also try a different USB cable. Or if you have USB hubs and adaptors between Teensy and your Mac, try to get a more direct connection.

Odds are very low Teensy is actually damaged, especially Teensy 3.2 which has a very robust voltage regulator.

[cageycruz]

Try a different computer.

Also try a different USB cable. Or if you have USB hubs and adaptors between Teensy and your Mac, try to get a more direct connection. ...

I borrowed a friend's MacBook Pro, an older version running 10.15 and used a different USB cable and yes to my surprise that did work.

So I tried the known good USB cable with my MacBook Pro and nope same download error. I then tried it without the USB hub, instead plugging into the Thunderbolt Dock and that worked. Strange.

Thanks for your suggestion.