I've decided to upgrade instead of fix a 3-year-old phone that was because even if I could fix the hardware I still would not be able to safely enable bluetooth due to an arbitrary code execution bug in android that was not patched. It was otherwise perfectly good for my needs. I could not install a custom ROM because my model was not well supported and any I could not rely on such ROMs passing safetynet/play secure checks which the extremely vulnerable OEM ROM would reliably pass.