They all pretty much function the same since CF is native IDE. There are cards that plug straight into the port without an ide cable which is nice, but probably won't work in your case since the card may block other cards. There are ones that stick out the back of your case mounted on a slot plate which are convenient but take a slot and internal via cable. Modern cards that are more than 4gb can pose problems running at the PIO mode that your ISA card uses however. I've had good luck with the Sandisk 50MB/s cards and transcend 133x cards.

You'll need either an LBA rom or overlay like EZ-Drive if you plan on a bigger than 504MB partition too.

True, perhaps he's lucky and is able to track down a BIOS from '94.
See paragraph "4.2. Is my BIOS Enhanced? How can I recognize this?"
ftp://ftp.nyme.hu/doc/eide/faq1.html

you can burn a XTIDE Rom and replace your Controller ROM with it.
It handles HDD's up to 120gb fine.

your controller comes with BIOS ?

Thanks for the comments.

I don't mind the 504 MB limit as long as the CF card is auto-detected by my old AMIBIOS and can be partiotioned using FDISK.

Not sure on IT-PACK4's BIOS, no signs shown during POST of it at least. The MB's AMI date is 060692 and auto-detect has already maxed out all params to get 504MB for my 540MB Seagate drive.

As an alternative for the main use case (swapping files), is replacing the 3.5" drive with GOTEK's floppy emulator (or similar product) a working option with my IT-PACK4 controller?

TamaMan wrote:

As an alternative for the main use case (swapping files), is replacing the 3.5" drive with GOTEK's floppy emulator (or similar product) a working option with my IT-PACK4 controller?

There are many ways to accomplish this, I guess you'll have to choose which one better suits your needs/configuration.
You can for example use an RW cd, but it's not practical if you transfer files too often.
Through the network (FTP) works the best for me, but it's not feasible for everyone (maybe your 486 doesn't have a network card or you can't run a cable to it)
A friend never closes his cases and he just connects the hdd to a dock on his main PC, but for this to work you need to be able to remove the hdd easily.
So yeah, get some ideas from people here and go with what fits your case more.

btw if you go the CF way make sure to get a card within your PC's limits. If you use some DDO software you won't be able to read the card on your modern PC.

Its likely the controller card doesn't have a ROM at all. It sounds like its a standard I/O card. The Gotek should work fine with it.