The magic bitmask question - again

Artem B. Bityutskiy dedekind at
Mon Oct 31 08:03:40 EST 2005

Fredrik Jönsson B (AL/EAB) wrote:
> This may be a stupid question, but I still need to ask.
> We have a system with a 128Mb NOR-flash of which 3Mb is used as a
> keep-off area for the kernel and the rest for a JFFS2 root file
> system.
128 Megabit?

> jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found at
> 0x00000000: 0x4800 instead
This message says that there is something unexpected at the offset 
0x00000000 of the JFFS2 partition. JFFS2 expects there is either a node 
there (most likely a clean marker node) or the block contains all 0xFF.

How can this garbage get into the beginning of an eraseblock? No idea. 
May be this is an effect of an unclean reboot? But if it happens often 
it is strange and looks like something not normal. Or the other 
possibility is that you did not erase your flash properly before putting 
the JFFS2 image there. And also it may be the result of hardware/driver 

Try to play with this. Try to erase the partition, check that it 
actually contain all 0xFFs, flash your image, compare with the original, 
mount and see is there are such messages.

Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.

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