Hi
There is no USB port visible to me, maybe on another HW version? Or is it internal? This one only has RS232 externally, and I did try reducing speeds of the com down to 300 baud or so, and various rates up to 115200.. When I connect with Cisco or Alcatel switches for example, the rate can determine if I am able to CLI with the device. But at any reasonable rate say 9600 it writes "erasing" then "Downloading" and finally the PC tells me it's done, but the 98 remains downloading indefinitely. I did swap over the EPROM from another 98 I had for drive issues, and although version was much older (1.81 vs 2.11) it worked right away. So it's definitely the EPROM thing not being able to complete the write and store cycles. Maybe bad memory sections?
As to a USB interface, quite often I do have a "USB Console" port on network devices (my real job) and find the interface over USB much better than the multi pin, and of course no wiring issues like crossed or straight or special pinouts. But I can't see such a connection on the 98 exterior.

No place like home
596 598 500+518+563.24 506.24 502 504 G98 Quad 34 FM4 405 306 909 Micro-Seiki and my Harbeth SHL5+ 40th Anniversary