Here are 3 ways to allow debugging on boot by connecting to adb. This is often called "insecure adb" - while it is not as insecure as you might thing 😉
Since A7 you have to authorize your adb server which either requires to add your adb pub key into the ramdisk (directly on / ) or you must put it in /data/misc/adb/adb_keys, e.g when in recovery. Details here.
important is that it has to have proper label and permission set. e.g when in recovery:
FORMAT(!) DATA in recovery!
REBOOT from recovery into recovery afterwards!
then go on:
adb push ~/.android/adbkey.pub /tmp/
adb shell
mkdir -p /data/misc/adb/
mv /tmp/adbkey.pub /data/misc/adb/adb_keys
chcon u:object_r:adb_keys_file:s0 /data/misc/adb/adb_keys
chown system:shell /data/misc/adb/adb_keys
chmod 640 /data/misc/adb/adb_keys
Choose an option and follow
depending on the device you could unpack/repack your boot.img by one of
- AIK
- abootimg - which is also part of mAid
- bootimgtool - which is also part of mAid
Whatever you use try first to: unpack -> repack -> flash (so without any modifications).
if that does not boot anymore use another tool. e.g. AIK does not work for the LG G4 sometimes so I use bootimgtool (-v qcom) instead.
default.prop (on newer android this might be named build.prop):
------------------------
ro.adb.secure=0
ro.secure=0
ro.debuggable=1
persist.service.adb.enable=1
persist.service.debuggable=1
persist.sys.usb.config=adb
# if that does not work try: persist.sys.usb.config=mtp,adb
Important:
remove ANY other line which contains one of settings above!!
when on a12 (and likely later) and you just wanna enable adb logcat during build (not truly insecure, its more like half-insecure): https://github.com/crdroidandroid/android_build/commit/a9f4cd5493ead4134aba6e17e80c81eb104cdf43
for a full insecure (i.e allowing adb root and then e.g. adb shell dmesg during boot) use one of the other options.
Within your android source directory (replace <ROM> with the vendor path of your ROM you building for. e.g vendor/lineage/config/common.mk)
sed -i "s/secure=./secure=0/g" build/core/main.mk
sed -i "s/secure=./secure=0/g" vendor/<ROM>/config/common.mk