It depends on which version of Grub you are using.
If you are using Grub legacy, open the file /mnt/sda1/boot/grub/menu.lst, and edit it. Change sda1 to whatever partition you are using.
Edit the boot options to be something like this:
title Tiny Core 3.3
root (hd0,0)
kernel /tinycore_3.3/bzImage quiet tce=sda1 opt=sda1 home=sda1
initrd /tinycore_3.3/tinycore.gz
Change sda1 to whatever partition you are using. Notice it is in a few places.
If you also use backup, you can later edit /opt/.filetool.lst to remove all references to the opt and home directories.
You can edit this using a root text editor.
Open the terminal and type "sudo fluff" Go to /mnt/sda1/boot/grub/menu.lst. Highlight menu.lst, and click Edit.
This is only for version 3.3. If you are using an earlier version, you need another method of editing this file.
If you are using Grub 2, the process is completely different. If you are, let us know.