do you want to keep around such legacy code (increasing the maintenance load) in the codebase forever?
No I don't want to keep such code forever to maintain, mainly because it won't be needed forever. But dropping support for DOS will be a separate effort (with dedicated threads and announcements). I don't think it should be like "while we are here, let's also drop DOS", it's a bigger effort than "while we are here".
For example, some chips use the toggle bit detection to check for a finished write.
Do you know, are such chips marked in flashchips definition, how do we know which ones are like this? I understand from your words this is a subset of older non-SPI (LPC/FWH/parallel) flash chips but which ones?
Also relevant to delays: are those the same chips that need extra delay 1s? For context, comments here https://review.coreboot.org/c/flashrom/+/80807 Do you maybe remember how to find them in flashchips?
As I understand, there are some small(?) number of older(?) chips which need special treatment on delays, it would be so helpful to find out which ones exactly.
Focusing on the 99% might yield enormous cleanup opportunities.
Yes, that's a really good observation. I have such thoughts in the background.