Work fine:
Download the update without installing (inside dsm update utility)
connect in root with ssh
type:
Xpenology> sed 's/flashupdateDeb/flashupdateDeb1/' /autoupd@te.info > /autoupd@te.info1
Xpenology> mv /autoupd@te.info1 /autoupd@te.info
Then do the update.