not enough blocks for JFFS?

[Tim Wu]

Hi! Everybody:

The system I'm working on use a 4MB NOR flash.
The block size of the 4MB flash is 64KB.
It also has eight smaller(8KB) blocks at bottom.
Since, on this system, I don't have much data to write(less than 10KB),
a CRAMFS(readonly)+JFFS(writable) combination should be pretty good for me.

Here comes the problem.  The bootloader has occupied the first three 8KB 
blocks.  I have only five 8K blocks available for JFFS.  It always fails 
when I overwrite an existed file on the JFFS partition.

I've checked the mailing list archive.  It seems JFFS/JFFS2 needs at 
least five blocks to work and the number '5' is adjustable.  Could 
somebody tell me where I can modify in JFFS source to have it run on 
fewer blocks?

Thanks.