My first thought: How about using a current computer to run qemu then mounting the Lenny iso as an image and installing to a qemu hard drive? Then dd the hard drive image to your 32bit target. (That might need access to a hard drive caddy depending on how you can boot the 32bit target machine, so a 'hardware regress' I suppose).
My second thought: If target machine is bootable from a more recent live linux, try a debootstrap install of a minimal Lenny with networking (assuming you can connect target machine to a network, I'm guessing with a cable rather than wifi). Reboot and install more software as required.
#inicio de fichero
--format=bestvideo[height<=?480][fps<=?30]+bestaudio/best
#fin de fichero
My ~/.config/mpv/config#inicio
ytdl-format=bestvideo[height<=?480][fps<=?30]+bestaudio/best
ao=sndio
vo=gpu,xv
audio-pitch-correction=no
quiet=yes
pause=no
profile=fast
vd-lavc-skiploopfilter=all
#demuxer-cache-wait=yes
#demuxer-max-bytes=4MiB
#fin
Usage: mpv $YOUTUBE_URLUpgrade ASAP.