Is it possible to make a zip file, similar to the one that installs GApps, that stores ADB debug mode as a system setting? Maybe somehow modify a system bootup script to change the ADB debug mode setting to on? I'm setting up a testing environment, and I can't have a factory reset turn off ADB.
I think I've almost got it - I have a rooted deice using CWM recovery, and I am using SuperSU for root permission management. I unpacked the .zip that the CWM installs
su from, and added a modified
/system/build.prop to the update, as well as a command to turn on adb in
sqlite3, but I think it require root access, and
SuperSU has default access to
su set to 'prompt'. Is there a way I can modify it to be 'grant' by default?