Bad block markers in NAND flash

[niino]

I was wondering if the bad block markers of NAND flash can be changed (i.e. removed or added). That means: if I do a byte by byte transfer from NAND flash 1 to NAND flash 2 (assuming both are identical chips, and using flashing hardware that is not aware of bad block markers), will NAND flash 2 have the bad block markers of NAND flash 1 and lose it's own factory bad block markers? Or are they protected in some way?

[abyrvalg]

Bad block markers are software-level concept. Hardware has no knowledge about them at all. So they can be read/written/erased the same way as any other data.

[amyk]

From a random Samsung flash datasheet...

Identifying Initial Invalid Block(s)
All device locations are erased(FFh) except locations where the initial invalid block(s) information is written prior to shipping. The initial invalid block(s) status is defined by the 1st byte in the spare area. Samsung makes sure that the last page of every initial invalid block has non-FFh data at the column address of 2,048.The initial invalid block information is also erasable in most cases, and it is impossible to recover the information once it has been erased. Therefore, the system must be able to recognize the initial invalid block(s) based on the initial invalid block information and create the initial invalid block table via the following suggested flow chart(Figure 3). Any intentional erasure of the initial invalid block information is prohibited.