It's probably dancingbits 5. If you have a diskboot built with the wrong dancingbits, the camera will still try to run it, and crash immediately, so no LEDs will light even if the address is actually correct.
To determine if diskboot is properly encoded, you can verify the dancingbits values by examining the firmware dump. Again, comparison to firmwares with known values should get you there. You could also just try each encoding, although not being sure of an LED address will bring some uncertainty.
LED addresses are likely to be similar to other cameras, or can be found in the firmware dump, by comparison to cameras with known addresses. Note that the address generally won't be found as a literal, but as say 0xC0220000 + <some offset>
There is also some LED finder code floating around the forum. Be warned that randomly pokes unknown MMIO addresses, so may not be entirely safe.
Another option is to use "firm update" or cbasic loading. Firm update needs the FI2 keys (found in the dump, again refer to known cameras). Unlike diskboot, "firm update" will refuse to load a binary that isn't correctly encoded. cbaaisc loader doesn't need any encoding, but may need adjusting for the eventprocs on your camera. See
http://chdk.wikia.com/wiki/Canon_Basic/Scripts/Loadernote that SystemEventInit is likely not to exist on your camera, use System.Create instead
