Going to 4.4.4 CM11 to lollipop ATT M7

I've got hboot 1.57, 4.4.4., and the latest CM11 nightly. Unlocked bootloader, S-ON. I'm trying to flash the RUU_M7_UL_L50_SENSE60_MR_Cingular_US_7.23.502.1_Ra dio_4M.32.3218.06_10.46.1718.01L_release_424933_si gned_2 rom update from the HTC website. I keep getting an error 155 that it isn't the right rom image for my phone. I'm assuming I need to relock my bootloader for the update to take? Do I need to go back to full stock? I've googled a ton and cannot find an easy way to relock my bootloader. I'm not sure if it matters, but I no longer have the stock HTC usb cable so i'm using one that came with a dell windows tablet. Thanks for any help.