I have a few questions with my project. I made my very first PCB using fusion360 software and surface mount assembly by JLPCB. A teensy4, adafruit MPR121 touch sensor, and audio adaptor connect with headers, and there are 33 surface mount leds.
Amazingly enough, the pcb works! The feeling when those leds lit up, just wow lol. Thereís was just one thing, however...

The audio adaptor works, all of my audio synthesis and audio files stored in program memory work fine. But, The SD card is not recognized. On my custom pcb, the audio adaptor is ~3 inches away from the teensy, connected with traces.

Question 1:
Could it be the distance from the teensy that is causing the SD card to fail? I remember reading warnings about using long wires to connect the audio adaptor, but was hoping 3Ē traces would be ok. Anything else I could check?

My project uses 8 wav files that play from the SD card. In reality, a SD card is far more memory than I need. I have here 16MB flash memory chips from a reputable teensy distributor, so was thinking to use these instead. Maybe the SDcard failure was a hidden blessing after all.

Question 2:
Is there anything about the SD card failing that would also affect flash memory? Pins or distance from the teensy.

Question 3: is it possible to load files onto flash memory using a teensy 4 *without using copyfromSD*, since I have no SDcard?

I suppose I could build up the audio adaptor and use a second teensy with stacking headers to load and test the flash, then move the audio adaptor to the project pcb. Probably should do that anyway! But curious to know if I can load or change files on the flash without access to the SD card.

Thanks for any help!