Just to save some effort, here is the RUU Scotty wants you to run.
MD5:
It's always worth trying everything... You just never know
MD5:
Code:
630eaae52a612a7415362aa59ebc2e19
It's always worth trying everything... You just never know

this just all of a sudden popped into my head,from reading the above a while ago:
i assume you ran the 2.17 ruu in attempt to downgrade(wich is wat didnt work).
have you run the ruu for 2.89.651.2 710,your current firmware? if your device is "refurbished"(but not so much),its a long shot chance that a previous user of that device may have modified something trying to downgrade,or do something similar.
in this scenario,running the 2.89 ruu should restore any modified partitions,and let the unlock work. i think we are on track with some sort of hardware issue/mismatch,but a last ditch effort to avoid yelling at sprint or htc may be to run the current ruu. a factory reset in hboot immediately afterward prolly isnt neccessary,but prolly wouldnt hurt![]()
So glad to hear this! Thanks for the kind words, enjoy your rooted 3vo!