I'm no expert and not sure what the "auto detection" function is but from what I know, after connecting up the Jag and opening a command prompt inside the dumping directory I have to type in lo_inp -8 BJL_DUMP.BIN to get to the orange screen. Sounds like you did this from your post (unless there's an alternative way I'm unaware of) so next would be to type in:
BJL_DUMP try.rom 0 800000 0
I've never used the command with .exe after the BJL_DUMP part. Kinda automatically does that for you, to my knowledge and it might corrupt the entire command. Will have to try it sometime.
A countdown of kilobytes should start at the bottom of the command window. If the ROM is 4MB it'd say 4096 KB and begin reducing. Takes my XP machine 58 minutes to dump 4MB.
So, if you see the 'countdown' of KBs it's working.