7390: Fix replace kernel for 06.00 (refs #2244)

git-svn-id: file:///var/svn/freetz/trunk@11245 149334a1-2f27-0410-a3b9-fc62619ac1e6
fwmod: fix byte_to_mb to handle negativ values.


git-svn-id: file:///var/svn/freetz/trunk@11246 149334a1-2f27-0410-a3b9-fc62619ac1e6