Would be interesting to have a method to load or extract the EEPROM data such that it can be used at runtime. Might be interesting for quickly iterating on other PCI<->SATA bridge chips, virtio-blk or NVMe support also.
You can use a ssh client on your Mac if you like coding on your Mac. This allows you to use e.g. retro68 and nano from your Mac.
https://68kmla.org/bb/index.php?threads/ssheven-a-modern-ssh-client-for-mac-os-7-8-9.38593/
Nice I have some bombed boards I could use for ports.
Some additional ideas I'll throw in:
Integrate ram and e.g. zuluscsi on the mainboard
mini-ITX/ATX compatible layout
I'm not sure if RNDIS or USB-ECM drivers exist for OS9, but if they do, you could probably skip the ethernet adapter and just connect the phone directly for tethering.
alloca is usually implemented as a compiler builtin. It allocates a buffer on the stack. There is usually no library associated with it
In a lot of cases you can usually replace alloca calls with malloc / free. And it may be needed if you are low on stack space
I believe the missing part to get any accelerator working on Macs is timing/arbitration related to interfacing with the rest of the hardware. That's most likely why stuff like floppy and SCSI have some issues working.
If you just want to run software, but faster, without original hardware, then...