Introduction: by jt/Trash/Trash80to . . . whatever!
dougg3 has made the most incredible introductory post to date, period! It's quite the saga of creative hackery and collaborative effort by the 68kMLA Technical Unit's Boffins and a lot of cheerleading by the rest of us in the peanut gallery.
At p.17 a consensus was reached regarding the necessity for an index to this thread: for those wishing to read it in whole, for the rest who might want to take a peek at the highlights before diving in head first, and for the participants, to ease their search for the incredible amount of content produced along the way in dougg3's creative quest.
dougg3's left at least two of the "impossible dream" boot sequence hacks, windmills if you will, shattered along his path and the SAGA continues!
Kudos to dougg3, and a special commendation for his incredible achievements on his intrepid quest.
Where'd Dulcinea get to?
- First post (DIP ROM sockets, custom floppy disk blinking question mark icons)
- ASC tomfoolery
- ROM SIMM preliminary discussions and brainstorming
- olePigeon's Jolly Roger logo
- Arrival, assembly, and troubleshooting of the rev. 1 SIMM PCBs
- Brainstorming for programmability without the need for a chip burner and designing rev. 2 with that in mind
- tt's SE/30 with Power Mac startup chime
- Summary of changes in rev. 2 and later, additional changes
- IIci troubleshooting and power supply testing
- Back to programmer board R&D (and other expansion brainstorming)
- olePigeon's customized ROM
This is my first post, happy to have discovered this place! I've been lurking for the past weeks while working on my project. A year or so ago a coworker and I who are both classic Mac geeks were talking about how cool it would be to take a 68k Mac's ROM and modify it. We were mostly talking about changing the startup chime (but before anyone starts getting excited, I'm nowhere close to that yet).
A few weeks ago I got to thinking about it again and decided to do it. I have a couple of IIcis as well as several other machines, but I figured that the IIci would be a good one to play with since I have two of them so I can troubleshoot in case something goes wrong. When I was searching for info about pin-compatible chips for the IIci's ROMs, I stumbled upon these forums. In particular, I found Dennis Nedry's posts about his IIci ROM hacking. I thought it was pretty cool that someone else had already begun on a similar project, but I still wanted to do it myself as well. I'm not doing anything that will give my IIci more ROM capacity--just messing with the ROM.
I took the lesser of my two IIcis (won't power on unless it's been unplugged for a half hour and the sound is faint -- pretty sure it just needs new capacitors and a good cleaning) and started hacking on the motherboard! Removed the DIP ROMs intact with my trusty desoldering gun, replaced them with DIP sockets, and copied their contents over to some almost-pin-compatible flash chips (Greenliant GLS27SF010, formerly SST27SF010) using a Willem programmer. I would have forgotten about the floating programming pins if I hadn't read Dennis Nedry's posts--thanks for that! Got the IIci to boot from them, so I was in business to start customizing.
Anyway, I'm aware the IIci has a synthesized startup chime so it's probably not the best candidate for hacking that. I started disassembling the ROM using GNU binutils and some other free disassembler I found for Windows, but I lost my patience somewhere around where it was first writing to the VIA1 chip, and believe me, that's not very far into the boot process. It's tough to figure out exactly where the synthesized chime is generated. I decided to go for a simpler task and customize some of the startup icons.
I changed the floppy disk with blinking question mark icons to an alternating white and black Apple logo, redid the checksum (once again, credit to Dennis Nedry for his ROM checksum calculator!) and booted it up -- and here are the results!
I'm not sure if I'm going to go anywhere else with this project, but I just thought I'd share my initial IIci ROM hack. If anyone has any ideas about how to mess around with the IIci's synthesized sounds, I'd love to hear them, but I'm pretty sure the answer is going to be "diassemble it and find where the sounds are generated."