You should create freeboot first hand then remap it before flashing it to the console.
Providing you still got unmodified copy of your original NAND, try the following:
1. Flash the original unmodified NAND back to your console and see if it boots as normal into the original old dash.
2. If all is good, use that original unmodified dump to create freeboot image.
3. Flash that Freeboot image first without remapping and see what happens.
4. If it doesn't work (i.e. you get E79 error or just black screen with green light on) then remap the bad blocks in your freeboot image and re-flash again.
PS. If you're good enough you can actually remap a flash on the NAND directly using nandpro