Hi ulfr
Glad to hear you got it working. A minor point:
mkisofs -l -J -R -V TC-custom -no-emul-boot -boot-load-size 4 -boot-info-table -b boot/isolinux/isolinux.bin -c boot/isolinux/boot.cat -o my.iso myisofiles
isohybrid -o 64 my.iso
The -V TC-custom sets the volume ID, kind of like the volume label of a hard drive, and does not need to be called TC-custom.
And please use code tags when posting commands.