A system update could have been making important system configuration changes when it got interrupted.
You should have an incomplete ( Corrupted ) system, this is why you should never interrupt a System firmware update.
What to do now ?
First you need to unlock your bootloader at the HTC Dev website
After that, you can try to repair your device via Fastboot by
flashing the stock images back.
Considering the information I found suggest that you still have the update.zip and you might have a MTK CPU.
- You can alternatively try to flash the Firmware using SP Flash Tool
v5.17 or above.
You will need to extract your Update.zip file and find any .IMG files... E.g, boot.img, recovery.img and especially system.img
If you can find boot.img, try to flash that with Fastboot first... Then try the rest...
If you have an update that contains folders, you will have difficulty installing it without a custom recovery.
With SP Flash Tool, you DO NOT need to unlock your bootloader, as you can flash the bootloader also.
I can find only a few ROM - Firmware online, however the firmware I found doesn't have Gapps included ( Google Apps ) ...
Do you have an MTK CPU ?