I've unpacked the dra file in the past, i don't recall how exactly, but i think it's just signed hashes in ASCII fallowed by a couple of concatenated files, including a WinCE rom(which you can unpack with wince tools viewbin.exe/dumprom.exe) that contains the actual recovery firmware, you can ignore the other files, they're encrypted XPU apps...
Anyway, you can alter the rom contents, but the box will reject it, because if you do that, the rom hash will change(the one included at the top of the dra file) and you will not be able to sign the new hash...
If you're interested you can find the "normal" firmware for MEO boxes at
http://194.65.47.50/upgrade/upgrade-files/PKG.DIR