it won't boot
That's a rather bad description of the problem.
A harddisk partition is marked bootable in the partition table (using HDToolbox or the like). It does not need a boot block. And it will boot no matter if there are files on it or not. If there are no files, you get an empty DOS prompt.
So you should have a closer look where it gets stuck. If you see the insert-disk screen, check with HDToolbox if the partition is marked bootable.
If you get an empty DOS prompt although you think all the right files are installed, check with HDToolbox if there are multiple partitions marked as bootable and if the one you want to boot from has the highest priority.
If you get a DOS prompt with an error message, tell us what the message is.
If it ends with an empty screen with only the "Workbench screen" bar and no icons, boot from floppy, edit startup-sequence of the harddisk and remove the EndCLI command at the end. Then reboot from harddisk and look for error messages.
If something else happens, tell us.