Here's the problem
parsing dump into user and spare...
ECD error at block 0x359 (raw offset 0xdcf200), block will be remapped
ECD error at block 0x35a (raw offset 0xdd3400), block will be remapped
ECD error at block 0x362 (raw offset 0xdf4400), block will be remapped
done!
cleaning up stray remaps
block 0x359 had no remap, assigning remap block 0x3ff
block 0x35a had no remap, assigning remap block 0x3fe
block 0x362 had no remap, assigning remap block 0x3fd
done!
--remap summary--
0: source: 0x0359 dest: 0x03ff
1: source: 0x035a dest: 0x03fe
2: source: 0x0362 dest: 0x03fd
Your NAND didn't have any legitimate bad blocks.
What did you use to dump the NAND?
You're lucky as this area isn't vital and you can just set noremap=true which should solve the problem.