LATEST FIRMWARE
The 1.22.651.3 update comes with a firmware upgrade that upgrades the radio, PRI, etc. When running MeanROM ICS v1.4 or higher, the new firmware is not required, but it is recommended. Since the ROM will run with or without the firmware, you can install the latest version of MeanROM ICS and then install the firmware, or install the firmware first, then the ROM: order doesn't matter! What does matter is whether you are s-on (HTC unlocked) or s-off (LazyPanda). If you do run into trouble flashing the ROM first, however, try flashing the firmware (or radio) first to see if that solves the issue. So here's what you do:
Option 1 (s-on HTC unlocked): While there are other firmware bits in the latest RUU, people who are s-on can only update the radio at this time. For the 1.22.651.3 RUU, this appears to be OK and taking the radio firmware and not the PRI and other firmware bits seems to have little or no down side. So to update your radio firmware if you are HTC unlocked (s-on), flash
this filefrom recovery. Because you are HTC unlocked (s-on) it is flashed from recovery just as you'd flash a ROM (using "install" from TWRP). You do not load this from the bootloader!