[Q] How do I update my second hand HTC One M8? topic

Hi

Bricked my old 16gb HTC One M8 - sending to HTC for repair tomorrow.

Ordered a replacement 32gb HTC One M8 from Hong Kong. It was billed as 'new' but on arrival it appears to be S-OFF but locked. Full bootloader details below:

*** LOCKED ***
M8_UL_CA PVT SHIP S-OFF
CID-11111111
HBOOT-3.16.0.0000
RADIO-1.15.2133156.UA13G
OpenDSP-v38.2.2-00542-M8974.0311
OS-1.54.401.5
eMMC-boot 2048MB
Mar 22 2014,00:53:32.16037

Whenever I try to update OTA, it tells me my phone is not stock and the update doesn't install. I just want to get the phone back to stock with the latest OTA firmware, nothing more. What would my best course of action be here?