Well, it is of interest to me and also to you i can see . Layman's curiosity in my case but of more serious interest in your case. It's even kind of a fuzzy mystery to me why 37xx won't boot with it's own boot.bin and 34xx's fw_all.bin with HWID overides to 1101, when yet it not only boots but runs with the complete and unaltered 34xx fw. So my simplistic understanding (perhaps totally wrong) is that if the 37xx boot.bin has it's hwid overidden to 1376 combined with unaltered 34xx fw_all.bin, then going by the original hwid 1101 37xx boot.bin result, it still should not boot with the 37xx boot bin in any hwid guise or combination (or maybe worse than not boot), and as you found it doesn't work. I suppose it's all to do with loading addresses not being the same with the two different boot bins. If you find out, and can you explain it in small words - great! If you feel it would be akin to trying to teach a slug to dance the Macarina, then just say 'Have faith my son, and believe.....' i've had to accept such words previously.