Apple macintosh roms2/17/2023 ![]() ![]() I was able to boot the ROMs in Mini vMac and confirm that these were indeed the secret images that had already been discovered. Reports of the easter egg said that it could be found by jumping to address 0x41D89A. We knew we had a good dump and merge when strings on the file contained human readable textlike “ Chicago“, “ PACK” and “ CDEF” (if you have the byte order wrong these will be “ APKC“, etc). The m68k has a 16-bit wide bus, so each 128 KB 8-bit ROM has half a word and they need to be merged into a single 256 KB binary file. This exapnds the address space to 128 KB (1024 kilobits) compared to the 64 KB of the M27C512 programmable ROM. ![]() Since it is a mask ROM that can’t be reprogrammed there is no need for the programming pin (Thanks, Nick!). The pinout for the chips is the same as the M27C512 PROM, but with the Vpp pin reused for A17. We removed the two ROM chips (the ones in the middle of the board, above the VLSI ASIC that is the Integrated Woz Machine) and dumped them with my PROMdate device. It boots, but lacks any media, so we decided to do some further digital archeology. We found this Macintosh SE on the side of the road in Brooklyn and carried it to NYC Resistor. Read on for the reverse engineering details of how we recovered this and the other three photographs stored in the ROM, and some information about the Motorola 68000 era Macintosh. The rest of the image was skewed and distorted, so we knew that it wasn’t stored as an uncompressed bitmap.Īfter some investigation, we were able to decode the scrambled mess above and turn it into the full image with a hidden message from “ Thu, Nov 20, 1986“: Adam Mayer tested different stride widths and found that at 67 bytes (536 pixels across) there appeared to be some sort of image data that clearly was a picture of people. While digging through dumps generated from the Apple Mac SE ROM images we noticed that there was a large amount of non-code, non-audio data. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |