As discussed previously (TinyCore Linux 6.4.1), TinyCore Linux is meant to be portable and not installed to a hard drive. But it can be, and if you do do that (as I have), you might actually want to configure it. And have the configuration remain after you restart.
Boot/Kernel Parameters
When I did the HD install, I set one of the "Boot Options" as tce=sda1. I haven't managed to find this in the official docs yet, but it appears that, along with the "Tiny Core Extensions" from which the "tce" parameter gets its name, the Boot Options are stored in /mnt/sda1/tce/boot/extlinux/extlinux.conf . One of the lines is this:
APPEND initrd=/tce/boot/core.gz quiet tce=sda1 restore=sda1 home=sda1 opt=sda1 kmap=dvorak/dvorak waitusb=5:UUID="xxNxNNxN-NxNx-NNNx-xNNN-NNNxNxNxNxNN" tce=UUID="xxNxNNxN-NxNx-NNNx-xNNN-NNNxNxNxNxNN"
I'm interested to find "waitusb=5" in here: I didn't add it, apparently they've made it a default. In this case, I was looking for the Boot Options to remove "restore=sda1" - as I've suspected, my inclusion of it appears to be redundant when you also have "home=sda1".
Making /etc/ Changes Permanent
One way (probably not the best, but it works) to make /etc/ changes permanent (assuming you have a permanent /opt/ directory) is to edit /opt/.filetool.lst and add files/folders you want to be permanent. At the moment I have this:
opt home etc/passwd
The first two lines are default (with my configuration? or all?). I've added the last because I changed tc's shell to bash, and otherwise it wouldn't stick. Note the lack of a leading slash: it fails if you have one. It might be better to just say "etc" instead of naming a specific file, but for the moment I'm going with this. Like many things about TC, I wouldn't put a lot of reliance on this: it remembers ... most of the time.