Failed update, why (q0.17, FP3)

[molej]

On the topic of TWRP on a/b devices a good note from @AnotherElk here:

How to install TWRP before easy installer

You can use the Easy Installer to install /e/. You would need to unlock the bootloader to be able to use TWRP, because the Easy Installer process locks it. This will force a factory reset for security reasons, so your user data will be deleted. Having an unlocked bootloader has security implications you need to assess for your situation. Your data on the phone is encrypted by default, but you should set up a screen lock PIN or password (pattern is possible, too, but a bit impractical for…