So last week I had a P8A that crashed one day and refused to boot for quite awhile.
I wiped the device and eventually I was able to get it to fully boot and not shutdown. I reflashed GrapheneOS for good measure. It ran perfectly for 3-4 days.
Yesterday it powered off twice but booted back up. Later on in the day it crashed again and now refuses to fully boot almost every time. Sometimes it will get to the Google logo and sometimes it will make it to the GrapheneOS logo before shutting down. Twice it even completely booted up but when I tried to unlock, it shutdown. The data has been wiped, but to no avail.
My question is this, how can I determine what is causing the shutdown? I would like to be able to tell if this is hardware or software related. The phone stays powered on while it is in the bootloader or recovery.
Thanks.