By default, BlueZ stores its persistent data in /var/lib/bluetooth. This includes controller settings and information about paired devices. However, I'm working in a system where the /var directory is unreliable, so I wonder if there is any way I can change this directory?
I have seen examples where it can be changed during installation, with the "--localstatedir" flag, but I'm looking for a solution that doesn't require reinstallation.
Without reinstalling its not possible. Path is configured at compile time so recompilation and installation is required. You can replace STORAGEDIR macro with string which is read from main.conf to different path at runtime. After modifying these changes you can restart bluetoothd every time you change path then it works.