NAND chip addresses, bad blocks and firware flashing

[deebee123]

i have a box (aml) with a reman. NAND chip. it has most of its capacity but its safe to assume it has at least some bad blocks. stock recovery arrived broken and no found fix yet.
what i am trying to figure out is how these bad blocks are marked and if a bootable SD (my laptop isnt detecting any boxes on usb male to male cable) would likely write to or try to write to these bad addresses causing a bad write and a bricked device.

[mitchell4you]

Well... some nand broken devices...can still be usable
by using libreelec installed on a sdcard (it runs from the sdcard)

offcource..you need a supported device and a fast sdcard

just a thought...goodluck

[deebee123]

It's one of the infamous MXQ pro clone of a clone of a clone boxes
Right now the box functions properly except:

The stock recovery= dead android (cannot mount any internal source,
twrp sees 0 for all internal sources,
Device is not detected by USB may be my laptops fault.
reboot to boot loader loads as normal not to boot loader
board and fw is p212 indicating 905x SOC but the splash screen shows Amlogic S905 before the MBOX logo

needless to say with RM marked NAND and cobbled together software even a soft brick may well spell the end.
I guess I need to figure out how to determine the exact size of the formatted NAND partitions, versus the expected size based on no bad blocks. Then I will know how many bytes or blocks of X bytes were formatted out as bad.

I wanted to be able to toy with Roms update to better firmware and just have complete control on general , but without knowing if the bad blocks will remain unused or how to repair if not..........

It seems my best option is to leave it as is and toss it in the kids room, unless and until I get some info on how nand flashing works with bad blocks.