How to patch and sign android bootloader image to enable "volume_up" button? Had trouble with it for a long time because manufacturer disabled the button to unlock the rooting functionality.
I live in the U.S. and what was once the land of the free is now the land of the locked bootloader.  Good luck

https://www.geektrouble.info/explore/android/view/218873

"OEMs/SoC vendors implement a Chain of Trust which must have a hardware-backed root of trust - a cryptographic key. On boot every software component verifies the integrity of the next component before loading it in memory. This chain of trust starts with BootROM (the very first executable code which runs on Power ON) and ends at /system and /vendor partitions. Everything in between - bootloaders, Device Tree, Linux kernel and Android OS code - is verified to be unaltered."