Amiga 1000 boot ROM & Kickstart 27.5(!)

From: Derek Peschel <dpeschel_at_u.washington.edu>
Date: Wed Feb 24 18:05:14 1999

Eric Smith wrote:
> John Foust wrote:

> > No, that's the point - Amiga Kickstart was the ROM, loaded from disk
> > into RAM. The Workbench OS disk was loaded second, after the Kickstart.

> Well, if it's the Kickstart code you're trying to extract, I don't understand
> why you need to do wacky things with the RESET instruction and fast memory.
> The Kickstart code is right on the floppy disk, plain as day.

*sigh* Should I get involved? It's really not that complicated.

Amiga 1000 Newer Amigas

1. Using "pre-boot" ROM,
   load Kickstart from disk;
   stash Kickstart on daughterboard
   and switch off "pre-boot" ROM.

2. Using Kickstart "ROM" (on the 1. Using Kickstart ROM,
   daugherboard), load Workbench OS load Workbench OS from disk.
   from disk.

3. The OS is booted now. 2. The OS is booted now.

John (or whoever -- I can't keep track!) wants to extract the "pre-boot" ROM
that is unique to the Amiga 1000. Not the Kickstart ROM, not the Kickstart
disk image, not the Workbench OS. The RESET instruction is just a fancy
means to write a program (which runs after the OS has been booted) which
switches the switched-out ROM back in. As other people have pointed out,
putting the actual chip into a ROM reader is an alternate solution.

I must say that one of the few Amigas I've used was a 1000, and I remember
the boot process all too well. It was very slow without a hard drive!

All the "pre-boot" ROM does (as far as I can tell) is to show an animation
of a disk being inserted, and read a bunch of sectors from the disk, and
switch itself off.

-- Derek
Received on Wed Feb 24 1999 - 18:05:14 GMT