Unlocking bootloader to change rom or firmware

Question

My question is very easy: do I have to unlock the bootloader on every single phone to change its rom or its firmware, or someone need it and someone doesn't?


— Federico Meroi | Sources

Answer

The answer is also easy: some don't need it.



Most if not all AT&T/Verizon/Amazon devices are bootloader locked, yet some are popular enough that devs worked ways around it. A common-sight solution is called Safestrap.





Do note that, with the lockdown measure becoming heavier over the years, there's no such solution I know of for recent devices. Even for older devices, Safestrap took a considerable long time to be developed/ported.


— Andy Yan | Sources

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