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It's not uncommon for declroms to have MacsBug symbols. Even the ROM on the big A/ROSE-based Ethernet card has them (for the on-card 68000 routines, which is nice).

As far as I know it's original. Some of them are just in blue for reasons I don't understand.

There is a specific place software looks for the slot interrupt status (and to clear it), called VIA 2. On a IIcx or SE/30 it's a real physical VIA chip. But on the Classic II that's buried inside Eagle for cost reduction, and the pins that would normally go to it seemingly have other uses.

Oh, here's the official Classic II schematic, in case I haven't posted it before.

Comparing the Classic II and LC II schematics, the major thing is that EAGLE lacks the SLOTIRQ pins. That's kind of a killer, because it means there's no way to route into the pseudo VIA2's interrupt flags.

DP83902s are commonly found in vintage PC ISA NE2000 cards. The struggle is finding an eBay listing for one where you can actually read the chip number in the photo.

Chips dying is pretty uncommon. I'd be suspicious of the non-replaced electrolytics that look fine, especially if they're anywhere near the NuBus chip or the slots. Could also be damage from previously replaced caps that didn't surface until now.

I assume you've checked the .Sony driver source in the SuperMario tree to see if that mode was used? I'd suspect any weirdness in the chip was for Twiggy drives, except that no machine with Twiggy drives used the IWM as far as I'm aware. (Lisa 1 had the 6 chips from the Disk II controller card...

Correct, millions is always in color. Probably because 24-bit pure grayscale is really just 256 shades.

For reference, there are 2 modes in the DeclROM: 1024x768 and 1280x960. No idea yet how it determines which one.

Fry's was legendary back on the pre-1994 Internet, and it lived up to the hype when I actually got to go to one in early 2003 (the San Diego Mission Valley location). MicroCenter is the closest thing to it that exists now, but they don't carry loose chips or anything like that. I'm a little...

Were you able to get the DeclROM from it, either directly or via software? Might be interesting to SlotsParse it and see what the listed resolution(s) are.

You're right, /ENBL1 and /ENBL2 do work, unless you're mixing drive types in which case external help is necessary.

In fairness to Woz, the VIA bit stuff is because the Disk II didn't need a head select, and there was something wrong with the drive select on the IWM that never got fixed. Drive select on the Disk II did work, and on SWIM1 the built-in IWM's drive select does work. Bonus Apple weirdness...

The original 3Com/Apple Ethernet NuBus board design and its many, many 3rd party clones are in fact a Mac "port" of the NE2000. Same chips, driver software works the same way, just the bus interface is different.

The developer note for the original LC mentions that netbooting has some support in the ROM and may be supported later. If I'm remembering correctly the Apple IIe Card supports netbooting the IIe, which was likely their major use case. (The Apple II Workstation Card and the Apple IIgs both...

Yes, MEMCjr has an integrated DAFB (video) chip.

Anyway, with this accelerator and the FDHD/IIx ROMs, you should be able to use any memory configuration that works for a IIx, IIcx, or SE/30.

GCR is always done in software (although the 13/16 sector Disk II upgrade did involve a new state machine PROM for the controller). But whereas IWM is essentially just a real-time shift register showing the most recent 8 bits to spin by the read/write head, SWIM does some extra processing...

The ROM code should detect IWM vs SWIM on any machine that would've had a SWIM. It definitely works in emulation. SWIM has a complete IWM inside for GCR (400K/800K) disks. Software can switch which of the two chips inside the chip is active and detect if the switching worked (which it of...