Modem stopped working on BH

[SwordfishII]

This is a documented issue with BH versions

Per 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).

https://wiki.pine64.org/index.php/PinePh...Braveheart