Well, I got new cables, had to set the ULTRA DMA mode to 3 because 4 or 5 wouldn't let me boot with the shielded 80-wire cables, got modern Linux working... aaand then broke it trying to install a desktop environment.
now Alpine Linux can't even see the motherboard's builtin ethernet controller, let alone the wifi card, the gpu isn't being properly detected and is still in 1024x768 mode (I mean that's kinda for the better), etc.

I think I'm gonna give up on Linux for this system for the time being, and just put Vista on it instead.

Some more retro BASIC stuff by me:

110 KEY 1, "SEND"
220 KEY 2, "QUIT"
330 ON KEY(1) GOSUB 190
440 ON KEY(2) GOSUB 230
550 KEY(1) ON
660 KEY(2) ON
770 KEY ON
880 CLS
990 OPEN "COM1:9600,N,8,1,BIN,CS0,DS0" AS #1
10100 ON COM(1) GOSUB 140
11110 COM(1) ON
12120 PRINT "Wait for data from Telnet (Port 2323)..."
13130 GOTO 130
14140 IF LOC(1) = 0 THEN RETURN
15150 B$ = INPUT$(1, #1)
16160 PRINT B$;
17170 RETURN
18180 COM(1) OFF: CLOSE #1: END
19190 LINE INPUT "Enter data to send: "; I$
20200 IF LEN(I$) > 0 THEN PRINT #1, I$;
21210 RETURN
22220 END
23230 RETURN 220

I figured out how to use the ON COM statement. I don't have any old hardware to try this on but it does connect to telnet client in Windows.

https://github.com/PeterSwinkels/COM-port-cli … asic-/tree/main