GrapheneOS, a privacy and security-focused Android-based operating system, has posted a series of tweets on X suggesting that Android should introduce frequent auto-reboots to make it harder for forensic software vendors to exploit firmware flaws and spy on the users.
As far as I know they only accept Pixel devices because they are the only devices on the market that allow locking the bootloader after installation and also because of the Titan coprocessor which greatly increases system security
There’s also a third reason, which is regular and timely firmware updates. One of the reasons why the GrapheneOS team rejected the Fairphone was due to the lack of proper firmware updates.
I remember I was not able to re-lock bootloader after custom rom installation, so you’re probably right. Unfortunately there are not many phones left to install custom ROMs except Chinese ones :/
AFAIK on Xiaomi Mi A2 lite if I flash back the stock fastboot ROM (I had it do it once because I crippled the partition images (this phone is A/B partition device)) it locks your bootloader and you have to unlock it again. I don’t know if this applyes to MIUI/Hyper OS phones too, because Mi A2 Lite uses near to stock Android.
Why would I want to lock the bootloader? I like having freedom 9f OS, I don’t want to replace one OS I’m locked into with a different, albeit more privacy friendly one. Most laptops have unlocked bootloaders.