[yjftsjthsd-h]

Sure, lack of secure boot is a tradeoff. Of course, by the same token you can just reflash the boot partition and fix that.

[netsharc]

How does flashing work, who controls the writes? I remember reading about hacking the controller of an SD card to override the read/write functionality.

I think if the bootloader is overwritable, it could lie to you about reflashing the boot partition...

[yjftsjthsd-h]

It varies by device. Obviously something has to handle writes, but generally it's a lower stage that isn't easily writable itself.