the stick is a disk now, no bios involved: usb grew enumeration and bot/scsi, fat12 picks whichever backend came up. qemu took the whole chain first try. the laptop found the stick on port 0 and then refused to reset it (my fault), the 50ms delay was port-0x80 writes that only cost real time inside qemu, so there’s a pit-based clock now. plot twist from the log meanwhile: the bios path worked on the laptop, because the toggles that “didn’t help” had quietly moved the stick to floppy emulation, and that path survives the mode switch. so it (partially) boots by accident while we fix it on purpose. also caught in a self-audit: a stall burned a full second, and a short read could report success with half a sector. readme rewritten as i was told to by sw.