Just do in bootloader
1) fastboot oem rebootRUU
2) fastboot erase cache
3) fastboot flash zip firmware1.55MOD.zip -- in this point please wait a moment
4) fastboot reboot-bootloader
optional reboot in recovery for test
Important: The flash process halts at around 75% to 90% on phone screen! This is normal and a safety precaution!
The last few percent is the reboot, which is NOT happening automatically, so you get a chance to check the console output before
reboot to make sure it is safe to reboot!
note: if needed for another hboot just tell me
Update: 1.57 https://mega.co.nz/#!1Q9yCSrD!fNdHv3...Eksx_offKvdxzw