HTC One M8 Software version screenThe HTC One M8 recently received an OTA to software version 1.54.651.8, which included several enhancements to both the radios and included the extreme power saving mode that has been much hyped for its potential five hours of runtime per 1% battery.

If you’ve rooted and replaced your stock recovery with a custom one, you’ll no doubt have noticed you can’t do an OTA update, but you can download a new base image and flash it over your old ROM, essentially recreating an OTA update.

However, flashing a ROM doesn’t get you the radio updates, which seem to be required to fix this, that, and the other that your carrier will have messed up while rushing things to market.

Thankfully, a developer we’ve written about a lot in the past, Captain_Throwback, has released a firmware update for the One M8 that updates the phone without too much hullabaloo.

There are two methods for updating the firmware, the first being to place it on an external SD card and name it 0P6BIMG.zip – that’s Zero Pee Six Bee I (as in icon), M (as in Mary), G as in the HTC EVO 4G.

That works fine if you’ve got an external SD card laying around, but if you just have a computer you can download the firmware update and use fastboot to flash it. Detailed, easily follow-able instructions are located at the source link below.

If you’re just interested in updating the firmware and not particularly interested in changing your ROM, it doesn’t appear that the newer firmware has any negative interactions with the old ROM software; however, your mileage may vary based on carrier, software versions, time of day, weight and airspeed velocity of an unladen swallow.

It should be noted that after flashing and rebooting your device, there will be no indication available in your ROM about the firmware being updated, as the software version you’re running has no relation to the firmware version. If you’re curious whether it actually flashed, reboot into the bootloader and you’ll see.

[theMikMik]