If your 386/486 has a pci slot (assuming due to your BIOS screen) i'd recommend a PCI UDMA IDE card.
ISA, EISA, and VLB ide tech is limiting. (also 504mb)
Your system doesn't support UDMA is why it doesn't see beyond 504mb. in DOS.
However if you have a built in IDE on the motherboard, and not an addon IDE card , you can add a dynamic drive overlay software that overcomes that limitation.
As far as using it formatted from a machine with UDMA which i'll assume thats the cse here, you may run into trouble.
I'd recommend using 504mb dos formatted limitation if i were not fault tollerant.
Myself, in this situation I would try to see if it works at full capacity to see the result because it cannot cause permanent damage.
Disk corruption through limitation rarely causes permanent damage and just for testing I would say see if it works.
I have overcome 128gb fat32 limitation but in testing discovered the corruption that can be caused and it wasn't permanent.

zapbuzz wrote on 2021-08-12, 10:18:

If your 386/486 has a pci slot (assuming due to your BIOS screen) i'd recommend a PCI UDMA IDE card. ISA, EISA, and VLB ide tec […]
Show full quote

If your 386/486 has a pci slot (assuming due to your BIOS screen) i'd recommend a PCI UDMA IDE card.
ISA, EISA, and VLB ide tech is limiting. (also 504mb)
Your system doesn't support UDMA is why it doesn't see beyond 504mb. in DOS.
However if you have a built in IDE on the motherboard, and not an addon IDE card , you can add a dynamic drive overlay software that overcomes that limitation.
As far as using it formatted from a machine with UDMA which i'll assume thats the cse here, you may run into trouble.
I'd recommend using 504mb dos formatted limitation if i were not fault tollerant.
Myself, in this situation I would try to see if it works at full capacity to see the result because it cannot cause permanent damage.
Disk corruption through limitation rarely causes permanent damage and just for testing I would say see if it works.
I have overcome 128gb fat32 limitation but in testing discovered the corruption that can be caused and it wasn't permanent.

Cheers for the reply. Unfortunately the DOS machine I have does not have PCI slots, just ISA and VLB so a no go then. But I do have a Pentium 1 system to build so all is not lost, I will use the bigger CF cards for that and just use my 512MB CF for DOS going forward. I will of course try the formatted fat32 CF disk on the DOS machine for an experiment some time, its only a games machine so I don't care about data corruption.

zapbuzz wrote on 2021-08-12, 10:18:

Your system doesn't support UDMA is why it doesn't see beyond 504mb. in DOS.

UDMA support has nothing in common with size of supported HDD. UDMA support is "hardware thing", HDD size limit is BIOS (software) thing.
Short overview - https://tldp.org/HOWTO/Large-Disk-HOWTO-4.html
More in detail - http://web.allensmith.net/Storage/HDDlimit/Limits.htm

You can overcome it by using the XT-IDE. This is EPROM chip programmed with BIOS module you can place i.e. in (usually empty) socket on Ethernet card.
There are many topics covering it. Just search the forum for XTIDE term.
"Pure software" alternative is i.e. EZ-Drive Dynamic Drive Overlay - drive overlay software mentioned already by zapbuzz.

zyga64 wrote on 2021-08-12, 11:46:

UDMA support has nothing in common with size of supported HDD. UDMA support is "hardware thing", HDD size limit is BIOS (softwar […]
Show full quote

zapbuzz wrote on 2021-08-12, 10:18:

Your system doesn't support UDMA is why it doesn't see beyond 504mb. in DOS.

UDMA support has nothing in common with size of supported HDD. UDMA support is "hardware thing", HDD size limit is BIOS (software) thing.
Short overview - https://tldp.org/HOWTO/Large-Disk-HOWTO-4.html
More in detail - http://web.allensmith.net/Storage/HDDlimit/Limits.htm

You can overcome it by using the XT-IDE. This is EPROM chip programmed with BIOS module you can place i.e. in (usually empty) socket on Ethernet card.
There are many topics covering it. Just search the forum for XTIDE term.
"Pure software" alternative is i.e. EZ-Drive Dynamic Drive Overlay - drive overlay software mentioned already by zapbuzz.

OK so it is maybe possible, I will try this weekend with EZ-Drive to see how that goes. Does it matter that the cylinder size is different to 1023?

It is common for cylinder size reported to be different in BIOS vs DOS so I wouldn't let that hold you back.

Thanks.