ANSWERED Regarding bad blocks - Semi-noob :)

[RedFarmer]

As this board always seem to have good answers to my qustions i just want to shoot a couple more to get a better understanding regarding bad blocks.

First:
If i read the NAND and get a bad block which is remapped, won't the dumped image already contain the remap-instruction for this block? If so, why do i need to manually remap afterwards? Is it because when i create a freeboot image from an original NAND, this information isn't carried over?

Second:
Is it possible that you sometimes can ignore a bad block, and if so, in which cases?

Third:
How come a bad block can't contain data but can store a remap-instruction?

Thanks!

 

[Martin C]

I can answer #3 right off the bat.

"Third:
How come a bad block can't contain data but can store a remap-instruction?"

It can't.

The Xbox remaps bad blocks in address order and locates them at the end of the address space in reverse order.

For instance, 1st bad block it encounters will force it to look at 0x3FF. 2nd bad block will be looked for at 0x3FE, 3rd bad block at 0x3FD and so forth.

 

[RedFarmer]

Aha! So the blocks themselves doesn't tell anything? The console knows in itself that it need to look at 3FF, 3FE and so on?

Can i remap an original image and then create a freeboot, or do i need to remap the final freeboot image?

 

[M AzeeM K]

^ Usually, you have to remap the created freeBOOT image as if it had the bad blocks at exactly the same place as the Original image. But first, do try if the freeBOOT image works on the Xbox360 without remapping. If it does, then no need to remap. But if it doesn't, then the remapping should be done.

This here is my personal opinion. Usually, it so happens that since remapping takes only a couple of minutes, one does it without checking whether if the unremapped image works or not.

 

[xColorado880]

Most the time the unmapped image works for me.

If you have any bad blocks within the first 50, try writing xellous first and it will remap them for you.

 

[RedFarmer]

Thanks guys! Good info!

If a bad block developes over time, is the console able to remap it? I mean, if a block goes bad, how can it get "backed up" at the end of NAND?

 

[Martin C]

I don't think they go bad. I believe that at the point of the NAND being written to for the first time, any read/write errors invoke the remap process (which is why on some consoles you can still read/write to the supposed bad block.

 

[RedFarmer]

I thank you for great answers and will post again if questions arise