Nor flash bad block

#1

hello,
I noticed that my nor flash looks like a bad block,md command to view, display the following content

MT7628 # md bc400000
bc400000: baddbadd baddbadd baddbadd baddbadd    ................
bc400010: baddbadd baddbadd baddbadd baddbadd    ................
bc400020: baddbadd baddbadd baddbadd baddbadd    ................
bc400030: baddbadd baddbadd baddbadd baddbadd    ................
bc400040: baddbadd baddbadd baddbadd baddbadd    ................
bc400050: baddbadd baddbadd baddbadd baddbadd    ................
bc400060: baddbadd baddbadd baddbadd baddbadd    ................
bc400070: baddbadd baddbadd baddbadd baddbadd    ................
bc400080: baddbadd baddbadd baddbadd baddbadd    ................
bc400090: baddbadd baddbadd baddbadd baddbadd    ................
bc4000a0: baddbadd baddbadd baddbadd baddbadd    ................
bc4000b0: baddbadd baddbadd baddbadd baddbadd    ................
bc4000c0: baddbadd baddbadd baddbadd baddbadd    ................
bc4000d0: baddbadd baddbadd baddbadd baddbadd    ................
bc4000e0: baddbadd baddbadd baddbadd baddbadd    ................
bc4000f0: baddbadd baddbadd baddbadd baddbadd    ................

MT7628 # md bc300000
bc300000: ffffffff ffffffff ffffffff ffffffff    ................
bc300010: ffffffff ffffffff ffffffff ffffffff    ................
bc300020: ffffffff ffffffff ffffffff ffffffff    ................
bc300030: ffffffff ffffffff ffffffff ffffffff    ................
bc300040: ffffffff ffffffff ffffffff ffffffff    ................
bc300050: ffffffff ffffffff ffffffff ffffffff    ................
bc300060: ffffffff ffffffff ffffffff ffffffff    ................
bc300070: ffffffff ffffffff ffffffff ffffffff    ................
bc300080: ffffffff ffffffff ffffffff ffffffff    ................
bc300090: ffffffff ffffffff ffffffff ffffffff    ................
bc3000a0: ffffffff ffffffff ffffffff ffffffff    ................
bc3000b0: ffffffff ffffffff ffffffff ffffffff    ................
bc3000c0: ffffffff ffffffff ffffffff ffffffff    ................
bc3000d0: ffffffff ffffffff ffffffff ffffffff    ................
bc3000e0: ffffffff ffffffff ffffffff ffffffff    ................
bc3000f0: ffffffff ffffffff ffffffff ffffffff    ................

Flash seems to be broken from 4 megabytes, but I haven't been using flash for a long time and haven't been writing much.
Does anyone have the same problem?

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#2
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#3

baddbadd can be a placeholder that indicates any form of "bad" error, potentially including even simply "this memory region does not exist".

Are you sure you even have more than 4MB of flash??? If EVERYTHING past 4MB reports "baddbadd" my first guess would be that you're trying to read from memory that simply does not exist. You didn't state what device this is.

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#4

thanks for your reply
I'm pretty sure my falsh has 16M

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#5

I occasionally encounter bad blocks on nand, but nand has corresponding bad block handling, and nor doesn't seem to have it

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