If after rebooting to normal mode the devices is lost

[ofilin]

!!!You follow all instructions at your own risk!!!
I encountered a problem when the patch only works in root mode, if you boot the phone without root, bluetooth devices disappear. So I found a way out on my Galaxy S10. The point is to flash the patched module into the firmware. Now on my smartphone, bluetooth works with any reboot and devices are not lost. Maybe someone will find it useful.

Install maagisk...

All command running in adb shell

su
mkdir -p /sdcard/Download/magisk/orig/
mkdir -p /sdcard/Download/magisk/patched/

md5sum /system/lib64/libbluetooth.so # MD5_1
cp /system/lib64/libbluetooth.so /sdcard/Download/magisk/orig/libbluetooth.so # Backup original module

Install BluetoothLibraryPatcher... Next:

mount -o remount,rw /vendor
for i in `grep -lr 'security.wsm' /vendor/etc/vintf`; do [ ! -z $i ] && sed -i "$((`awk '/security.wsm/ {print FNR}' $i`-1)),/<\/hal>/d" $i; done
mount -o remount,ro /vendor

reboot 

su

md5sum /system/lib64/libbluetooth.so # MD5_2. Should not match MD5_1

if MD5_2 != MD5_1
cp /system/lib64/libbluetooth.so /sdcard/Download/magisk/patched/libbluetooth.so
And uninstall BluetoothLibraryPatcher

reboot

su
md5sum /system/lib64/libbluetooth.so # if MD5_1 do:

mount -o remount,rw /
cp /sdcard/Download/magisk/patched/libbluetooth.so /system/lib64/libbluetooth.so
mount -o remount,ro /
reboot

All done!
Now bluetooth on your smartphone will work without the Bluetooth Library Patcher module

[dwildstr]

Great guide (not sure it's an "issue", but dunno where else is a good place for it)! In a Galaxy S10 booting into Magisk is so fussy (you need a live data connection on USB to initiate recovery mode) that it seems like half the time I boot into non-Magisk mode and lose my Bluetooth connections, so this si a very welcome fix!

My only modification, on a Samsung Galaxy S10e (G970FXXSGHWB3), is that /system/lib64/libbluetooth.so is a read-only mount unto itself, so copying over the patched library requires the lines

mount -o remount,rw /system/lib64/libbluetooth.so
cp /sdcard/Download/magisk/patched/libbluetooth.so /system/lib64/libbluetooth.so
mount -o remount,ro /system/lib64/libbluetooth.so

instead of just a remount of the root directory.