hi Dancemammal,
you said "some of the Actions Firmware is encrypted with a hash" do you check the soft that i told you "mp3fwtools"?
http://www.mympxplayer.org/tool-mp3f...ish-df675.html
this soft can open actions fw encrypted. if you look into the folder, there is a file dll, call it EncryptDll.dll maybe can help you to break the hash.
good luck