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Participant saleksin
Participant
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Bootrom and bad blocks in NAND

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How, if at all, bootrom handles bad blocks in NAND flash during boot process? Does it read bad block table, or checks information in OOB memory of first page in block?

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Xilinx Employee
Xilinx Employee
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Re: Bootrom and bad blocks in NAND

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Hi  Saleksin,

 

The BootROM manages bad blocks in the following ways:
• It looks for a bad block table (BBT) in the last four blocks of the NAND flash device.
• It supports a primary and secondary BBT with versioning allowing safe software updates.
• If a BBT is not present, the BootROM scans the flash reading the out-of-band (OOB) information
to determine the locations of bad blocks.
• The BootROM only performs read operations – it does not write to the flash.
While reading from NAND, the BootROM skips blocks that are marked as bad in the BBT, or in the
OOB information if a BBT does not exist.

 

For more information please read 6.3.5 NAND BOOT in ug585.

 

Best Regards,
Srikanth
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2 Replies
Xilinx Employee
Xilinx Employee
293 Views

Re: Bootrom and bad blocks in NAND

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Hi  Saleksin,

 

The BootROM manages bad blocks in the following ways:
• It looks for a bad block table (BBT) in the last four blocks of the NAND flash device.
• It supports a primary and secondary BBT with versioning allowing safe software updates.
• If a BBT is not present, the BootROM scans the flash reading the out-of-band (OOB) information
to determine the locations of bad blocks.
• The BootROM only performs read operations – it does not write to the flash.
While reading from NAND, the BootROM skips blocks that are marked as bad in the BBT, or in the
OOB information if a BBT does not exist.

 

For more information please read 6.3.5 NAND BOOT in ug585.

 

Best Regards,
Srikanth
----------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful and reply oriented.

 

Participant saleksin
Participant
177 Views

Re: Bootrom and bad blocks in NAND

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Many thanks!
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