I already mentioned this in #133, but I think a separate issue will make things easier to manage:

manage_ocden_fuse_bit: true seemingly enables signature verification even if it's set to disabled with signature_verification: false. To reproduce:

1. Use an ATMEGA1284 as the target (set target name to atmega1284) or a target with a signature mismatch between the detected one and the one in the .xml definition file.
2. Set manage_ocden_fuse_bit: true and signature_verification: false
3. Start bloom. You will get an error: [ERROR] Failed to validate connected target - target signature mismatch.