[Yaffs] yaffs2 - resize up

Hi,

I would like to resize up a partition in a special use case.

I have a 256MB nand chip with 2 yaffs partitions
    /boot of 32MB - nand blocks from 1 to 261
    /usr of 128MB - nand blocks from 262 to 1290
nand blocks from 1291 to 2047 was never used and are clean
The resize will be done only once and at boot time. /usr will be increased
to 224MB (blocks from 262 to 2047)

Because of yaffs2 architecture, do you think it is possible to resize up
"/usr" partition without any issue on filesytem ?

Jean-Christophe
PS: my operating system is vxWorks