Backups are, first and foremost, your responsibility. It’s unfortunately not realistic to expect someone to diagnose whether an issue is software-related or a hardware failure on any obscure DIY OS you might have installed. But as long as it’s possible to flash back the original firmware, warranty should still apply
only fair if it does not come with any data loss. so basically not actually fair
Backups are, first and foremost, your responsibility. It’s unfortunately not realistic to expect someone to diagnose whether an issue is software-related or a hardware failure on any obscure DIY OS you might have installed. But as long as it’s possible to flash back the original firmware, warranty should still apply
Software can easily harm the actual device, so locking it to prevent that from happening in a warranty situation doesn’t seem super off-base to me.