[Q] Failure to update to Lollipop. Now what? topic

I have Vodafone IE HTC M8. I tried to upgrade to stock 5.0 (just recently arrived). As people advised, flashed stock recovery and started OTA upgrade... And got big red triangle... Have no idea why :( I managed to reboot (Power + VolUp). And ... Now I cannot get to recovery any more, the phone says "Software status: modified" and stays in the boot loader.

Any attempts to flash recovery fail with "signature verify fail". I tried various things: stock recovery, philz recovery. Same thing.

Any advice? I would really like to have recovery recovered...