I am seeing a growing discussion on the need for more Linux phones in the market given Google's problematic behaviour w.r.t the changes that will be introduced to that OS.

One very good point that some community member raised was that Android itself wasn't the problem but the locking of the bootloader in the phone. If the bootloader could be unlocked, then it significantly lowers the bar for the end user to install their OS of choice.

I have dabbled with flashing OSs in old smartphones (GrapheneOS, Post market and Lineage). I commend the developers because I could do that without truly having to "understand the code" at the lower levels. But I assume that was possible because the boot loader could be unlocked somehow*. It seems that isn't the case with many/most phone fro. Samsung / Xiomi, etc.

Are their bootloaders truly unlockable? Is it simply impossible to unlock and relock bootloaders?

• I know that with lineage, the bootloader couldn't be relocked and that was touted as a security flaw. If someone could explain why this lock/unlock is so complex, I'd appreciate it.