PinePhone modem keeps "disappearing"

[zetabeta]

Hmmm, before I start with that, one question: I see I can enter EDL/QDL mode with the instructions from:
* https://github.com/Biktorgj/quectel_eg25...l-with-adb
* https://xnux.eu/devices/feature/modem-pp...adb-access

but is there a way to get back out of that mode without flashing a firmware?

i think no, beyond reboot and/or removing battery. however, if usb connection stays stable in edl/qdl mode, i think there is an issue with firmware.

[Kevin Kofler]

So, to keep you updated: The last few weeks, the modem has been almost always down (or rather, disconnected from the USB bus). Sometimes, it has come up for a short moment, and the occasional SMS got delivered then, but it was immediately gone again.

Attempting to flash a new firmware is also not possible if the modem does not even show up on USB. But it all looks like a hardware fault anyway.

So unfortunately, the resolution is that I have to buy a replacement. I have ordered a new PinePhone from the EU store (hoping the 2 year warranty there will cover this type of defects – it should by EU laws). The defective one was ordered directly from the Pine Store because that was the only option at the time (April 2021, the EU store was opened July 2022).

[Kevin Kofler]

For the record, it turned out that it is not just the modem: That PinePhone's USB subsystem is completely messed up. It fails to work even with JumpDrive (the computer cannot see it on USB), whereas the new one I just received works just fine with the same JumpDrive image on the same microSD card, the same USB C-A cable and the same computer.

So I will have to resort to WiFi to transfer my data from the broken PinePhone to the new one.

[zetabeta]

For the record, it turned out that it is not just the modem: That PinePhone's USB subsystem is completely messed up. It fails to work even with JumpDrive (the computer cannot see it on USB), whereas the new one I just received works just fine with the same JumpDrive image on the same microSD card, the same USB C-A cable and the same computer.

So I will have to resort to WiFi to transfer my data from the broken PinePhone to the new one.

what i have looked the schematics, usb is in a soc chip. although other (physical) components or chips could be the cause as well. not necessarily conclusive, but this increases my feeling that we play some kind lottery game with quality of mainboard and soc chip.

[Kevin Kofler]

Since this is definitely a hardware issue (which I cannot fix) and the replacement I bought works (which also means I am not going to attempt any further debugging), I am marking this as resolved.