TinyCore in qemu save options

I ran

qemu-system-x86_64 -m 2047M -boot d -hda tc.vhd -cdrom TinyCore-current.iso

I installed Firefox and shut down the virtual machine. After rebooting with the same command, Firefox wasn't installed. How can I achieve that if I install something, it will persist in tc.vhd image? Has it something to do with the "save options" when shutting down the machine? There is a backup option, but it isn't offering the /dev/hda as I would expect.