The bios screen says it understands LBA, so it really should NOT be impacted by the 504mb limit imposed by the OG version of INT13. (which plagues 386s and early 486s) However, it might be affected by the 8gb "large CHS" limit.
Anyhow, that would not affect a 512mb drive.
I am not sure why your late era 486 is having these issues.
Clarification:
The early CHS addressing method ran into a brick wall when used with DOS. While INT13 could address drives larger, using more heads and more sectors per track, DOS has a restriction that reduces these values by 1, and it results in a maximum permitted drive geometry of 504mb. This is a limit usually found on XTs, 286s, and 386s, but some very early 486 boards are affected.
Your board's drive geometry screen says it knows how to talk LBA though, so it should not be impacted.
the 8gb limit is a similar situation, but with the "Large CHS" addressing method. With that, DOS cannot see drives larger than 8gb without help, such as from an option rom, or from a DDO.
Again though, your BIOS says it does LBA, and that should not be an issue. Your drive is also smaller than 8gb, so again, would not be an issue.
WHY IT MATTERS:
NT4 has to START with the DOS int13 interface, until it can load NTLDR , the HAL, and then the 32bit disk controller drivers (to enter LBA24 mode). This means the boot drive has to obey the limits of the INT13 implementation present. NT4 CAN use a DDO to get around this, since it only needs to be active during the first few seconds of the boot process, but it is not considered desirable.
