In my attempts to get a home built kernel running on my phone I’ve had quite a few times where things haven’t quite worked and I end up stuck at the HTC screen. As there isn’t any output via USB at that point it’s frustrating to know what the problem is, but there is a solution…

  1. Power off the phone (remove the battery)
  2. Start the phone in recovery
  3. Use adb to view the dmesg

This gives you the previous boot dmesg and hopefully more information about what went wrong 🙂