As for modding the recovery image to include adb in recovery mode, I am stuck. Instructions I
found refer to ramdisk contents, and as reported by Magisk this platform is ramdisk-less.
So currently I am not sure how to continue. After all, it is just a convenience of having adb enabled at boot and in recovery mode. Otherwise I will need to boot into fastboot.
Meanwhile, I use TotalCMD's handy shortcut-button to invoke the command su with the parameter:
Code:
settings put global development_settings_enabled 1; settings put global adb_enabled 1; echo "mtp,adb" > /data/property/persist.sys.usb.config
Which is equivalent to going to Dev Settings and toggling the USB Debugging.