Bluetooth: It is not clear to me yet, how he did that.
Microphone:
The default FYT firmwares use in config.txt:
Code:
persist.btmic.gain=7
persist.btspk.gain=7
Tyukta uses:
Code:
persist.sys.zlink.mic.vol=9.9
persist.audio.mic.senstivity=1
persist.btmic.gain=10
persist.btspk.gain=7
That obviously gives a clearer sound.
The core 6351_1.zip is actually universal (for FYT uis7862 units that is). If that is 100% true I don't know, but so far it is.
Modifications can be for screens in the config.txt: standard, Tesla style, etcetera
MCU firmware is definitely not universal.
The AllAppUpdate.bin is reseller dependent (ro.build.fytmanufacturer=<xyz> and sometimes sys.fyt.bluetooth_type=<x>). And in some cases the "non-standard" resolutions require other apps, because the FYT apps are terribly built and not according Android auto-size rules.
Tyukta has a lot of firmwares for the several reseller ids, but I think it can be done in one script. Check the reseller id and in the lsec script do a "sed" action to update to the correct reseller id. But I am still waiting for my unit to arrive, so I can't test.