Avoiding modem flash-memory corruption?

[msquared]

On the PinePhone Software Release page, it says:

There is a document about using the modem [...] disable the modem before power off is pretty essential to avoid corrupting your modem's flash memory.

I have a few questions:

• Do I still need to disable the modem before powering off the phone when I have powered up the phone with the modem off (via the kill switch)?
  
• If I've booted the phone with the modem off then subsequently turn off the modem via the kill switch, should I disable the modem before using the kill switch to turn off the modem?
  
• If the modem's flash memory has been corrupted, how can it be restored/recovered/reset?
  

[wibble]

The first one may depend on which distro you're using.
For the second, I'd play safe and disable the modem before operating the kill switch.
For recovery, no idea. There may be a document covering it on Quectel's web site.

[---]

Any update on this situation? Do we need to follow the wiki advice https://megous.com/dl/tmp/modem.txt?

[Awesomesauce71]

Any update on this situation? Do we need to follow the wiki advice https://megous.com/dl/tmp/modem.txt?

+1 any updates is this still necessary?

[wibble]

Which part? And which OS?

[heng]

Not on CE, because the hardware issue has been resolved, according to the Wiki:

Modem PWR_KEY signal resistor population

Resolved in v1.2 by separating the modem PWRKEY (PB3) and STATUS (PH9) signals.

On the dev phone (1.0) this signal was connected to PB3. This allows for turning on/off the modem via GPIO from a kernel driver. If proper power down is to be implemented in the kernel for the modem, to allow safe shutdown of the modem before turning off the 4g-pwr-bat, kernel has to be able to signal to the modem to shut down and wait 30s. This is not possible on braveheart. Without this signal, kernel can't do anything to shut down the modem, and would have to rely on userspace to properly manage the modem power up/down sequence. Relying on userspace risks users shutting down the modem without proper wait time of 30s, risking modem damage (flash data corruption).

[---]

Great - so just on the 'Scottish phone', thanks.