first of all the serial is not so good on linux, you have to deal with term/io2 (instead of term/io) if you got faster than 230400bps, it's not a problem but you have care about that if you use an abnormal serial device at 1Mbps which is the best you can have
btw 1Mbps is too slow for 512Kbyte of ram, it goes less than 100Kbyte/sec, so we are speaking about 5-6 seconds for the uploads
with 10Mbps (over ethernet, or over usb2), it's less than 1 second
it makes the differences if you do a lot of uploads in a day
also, in my home made 68k-board i have 512Kbyte of emulated rom, and i simply want a faster device!
p.s.
at the commercial side, it could be interesting for automotive applications