Thanks for answer. DOSBox is a great emulator and very useful not only to play, but also to debug. I'll give it a try and try to load the BIOS in memory and then do a JMP FFFF:0 Let's see if I can somehow get further.

Hi, I want to debug an old DOS BIOS and I wanted to know how can I do that from DosBox. Is there a way to load my own BIOS and have DosBox debugging it step by step? Thanks!