[Letux-kernel] Modem disappears GTA04A4

[Jake]

Hi,

I'm experiencing a problem with the modem disappearing on GTA04.
For example when writing text messages to and fro with suspends in
between it happens at times, that the modem /dev/ttyHS* files
disappear. The modem is still unblocked in rfkill. 

I don't have any logs yet. I usually powered off the GTA04A4, removed
the battery for a few seconds, reinserted and booted again to continue
the conversation as soon as possible.

How can I toggle the gpio 186? to reenable the modem manually?

My observations so far:
4.19-rc7: modem disappears sporadically
4.19.12: modem disappears sporadically
4.20: does not wake on incoming call/text
4.18.20: modem disappears

Thanks,
Jakob