Raspberry Pi Pico 2 doesn't appear when flashed with micropython

[imSarahOwl]

Recently I bought a Pico 2 with the RP2350 from Aliexpress for my micropython project.
After flashing it with micropython, /dev/ttyACM0 simply didn't appear. I've tested it with circuitpython and the pico-examples, and the serial port appears, only with micropython I can't get to the serial port.
dmesg gives me no output, and picotool says MicroPython is flashed
Program Information name: MicroPython version: v1.26.1 features: thread support USB REPL frozen modules: neopixel, dht, ds18x20, onewire, uasyncio, asyncio/stream, asyncio/lock, asyncio/funcs, asyncio/event, asyncio/core, asyncio, _boot_fat, _boot, rp2 binary start: 0x10000000 binary end: 0x1004f4a0 target chip: RP2350 image type: ARM Secure

What could be the issue?

[GitHubsSilverBullet]

What could be the issue?

First and foremost that we have no idea which board exactly.
If I had to hazard a guess, maybe it's using a cheap and slow FLASH chip and the standard Micropython clocks it to fast. A good macro-photo (of the FLASH chip) or the precise type could help.

[imSarahOwl]

It's a Tenstar RP2350, got it from aliexpress
Sorry for the nooby question, but where in the board is flash chip usually in?

[GitHubsSilverBullet]

Apparently they don't supply neither datasheet nor schematics.
That's the worst-case scenario!
»Caleful, if buying cheap flom Mistel Wong, plepale to get sclewed.«

[Josverl]

Another possible cause could be that the filesystem is corrupt and somehow stalls the boot.

mpflash --board RPI_PICO2 --erase
Should fix that.

That uses Phil Howard's Pico universal flash nuke , you can also use that directly

[imSarahOwl]

I tried using mpflash, but my version didn't have a --erase option. What version are you using?

[Josverl]

What version are you using

Latest is mpflash 1.26.6

I think I added that option around 1.24.x

One other potential cause is the Linux braille driver which sometimes grabs ports. Removal of that driver is a good workaround unless you depend on that.