[U-Boot] A command to discard saved environments?

[Wolfgang Denk]

Dear James,

In message <d18f75c7-388b-b607-ed70-64a250320d5a at gmail.com> you wrote:
> 
> > In your case, you could save the "erase" by overwriting the first 4
> > bytes (where the CRC32 checksum is stored) with 0xFFFFFFFF.

Wrong.  I meant writing 0x00000000 - as you can always write that,
setting any remaining 1 bits to 0 which does not require an erase of
the sector.

> In the case of my NOR flash storage, telling erase to do one byte 
> actually causes the erasure of an entire flash sector, which we've 
> reserved for the NV environment.  You are of course correct that 
> overwriting the CRC will have the same operational effect.

...and as the next "saveenv" will start with an erase, writing 0 to
the CRC 32 field saves you one erase cycle on that sector.

I know, this is nitpicking. Soryy.

> It's a rare occurrence that we need to do this, we don't use this sort 
> of operation as a normal part of doing business.

Agreed. This should never be part of regular operation.

Best regards,

Wolfgang Denk

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