As told before, Linux is not bootable on such old Processors.
BUT:
I've found ELKS, the Embeddeable Linux Kernel Subset
which runs on 8086 upwards.
I've tested the Version provided on https://github.com/jbruchon/elks/releases .
It boots properly on the TC64 and it even mounts the Harddrive (=SDcard) \0/
Howto: I've chosen the fd1440.bin Image. You need to rename it to nextboot.img and place it in the root of your sd card.
its a single user mode linuxish system, logis is "root", no passwd needed. Mount the HD with
cd /mnt
mkdir hdd
mount -t fat /dev/hda1 hdd
voila
yours
masterhit