2/17/2024 0 Comments Iwrite for apple![]() This contains a lot of info, and I had to do further disassembly throughout the program to understand what everything meant. Let’s look at one of the SIMM entries in detail: QuadraSIMM1. I would love to see an example of what these PDS cards looked like, if anyone out there has some inside knowledge they would be willing to share! You can even see in the main UI screenshots above that there was a separate “PDS ROM Info” section on the right. The names of these table entries, and the table itself, were assigned by me.Ī lot of the entries in this table are PDS cards. The holy grail was when I discovered this big table of entries for compatible ROMs. Fortunately, a lot of the functions in the program had their names present as a string directly afterward so it gave me some context about what was going on. ![]() In order to answer these questions, I had no choice but to start disassembling the Flasher™ utility. Would this utility even support any of my Macs? What kind of ROM module would I need? What would it take to get that Program button enabled? I wasn’t really sure where to begin though. This is all very interesting, but I wanted to see what it was like to actually flash a new ROM image. Then I could use the Verify button to show that my onboard ROM matched the dump: It defaulted to a filename of “Saved RomMondo”. This makes perfect sense, because it was just detecting my logic board’s mask ROM chips which are definitely not programmable.Īll I was able to do was go to the File menu and choose “Save Onboard ROM…” to dump my existing ROM. Hewitt as the author:Īs you can see, it says the SIMM type is “Read-Only ROM” and the Program button is grayed out. Here’s the About dialog, identifying Carl C. I ran it on my LC 475 and this is what it looked like: Of course, I had to download this utility and figure out how it works. It was recovered from a prototype PowerBook 520 purchased in 2020. ![]() I had verified that the write enable pin was going into the memory controller chip in several Mac models, so I was pretty confident that in-system programming was possible.Īs luck would have it, multiple people pointed out to me that an Apple internal utility used for ROM flashing had been uploaded to the Macintosh Garden. The reason I believed this is because the ROM SIMM socket in the Quadras brought out pins for 12V (VPP) and write enable (/WE). After I wrote about the possibility of programmable Mac ROM SIMMs in Quadras a couple of months ago, I suspected that there had been a way for developers at Apple in the 68k Mac era to reflash the ROM in their Macs during development, just like BIOS updates on PCs.
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