Forgive me I might not be following the addressing correctly.
The dumped code:
:20E000000D94F6F20D941FF30D941FF30D941FF30D941FF30D941FF30D941FF30D941FF392
Does sort of look like this from “stk500boot_v2_mega2560.hex”.
:10E000000D94F6F20D941FF30D941FF30D941FF36E
:10E010000D941FF30D941FF30D941FF30D941FF334
As you stated the first byte appears to be the length and the last byte perhaps a checksum. I've tried various avrdude dump formats to try and made the dump directly comparable without success. I used Intel hex (:i) option. I found a trial version of "Fairdell HexCmp2" and I've attached a screen dump of a file comparison. The results don't look the same.
