Not exactly. The Classic ROM is a single chip whereas the SE had two chips (like the Plus before it). In much the same way the Classic II had 2 chips on the early models and 4 chips on the later models. (Would be curious if those Classic II chips are swappable with an earlier Mac.) It almost seems like Apple intentionally varied the ROM configurations to prevent exactly this kind of thing.

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Ah, we don't sweat two chip vs. four chip, nor one chip vs. two chip. Those are hardware variations which do not affect the code and are easily worked around, in most cases.

It would probably be easy enough to take a ROM image from a Classic and span it across a pair of 8 bit wide chips of the type which will fit in the SE. Chip programmers typically have spanning as one of their software functions, so that ROM images can be divided amongst several chips.

It is a minor variation of code I am told by the Mini vMac Classic emulator developer specifically to support the backlight CDEV like the Portable. But otherwise they are identical.

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Is the Mini vMac developer approachable about such questions?

The reason I ask is because of the Outbound Model 125. In addition to a Plus or SE ROM installed in the machine, it has a pair of EEPROMs on board which are programmed with Outbound specific code. I would love for someone to take a look at it for a couple of purposes. Primarily, I want to modify it to support other hard drives. As written the code in the EEPROM only supports three or four size of hard drive, and I suspect that it could be made to support other larger drives.

In the longer term, I'd love a primer on how to learn my way around the ROM. Does he read machine language, or use a disassembler, or even a decompiler?