I had the same problem at the beginning as I was unlocked the bootloader with HTCDEV.
If you unlocked the bootloader with HTCDEV, you should flash the boot.img manually with fastboot
to get it fixed.
1). Switch off the phone and trun it on to bootloader and go to the fastboot
2). Connect the device to the pc and connect it with fastboot (CMD)
3). extract the custom firmware (.zip) file and find the boot.img
4). copy it to the location where your fastboot.exe located at (ex: C:\sdk\platform-tools\)
then flash it with
fastboot flash boot boot.img
Hope this help you