VRP5.1 implement licensing system. License consist in two files wich should be copied on router:license.txt and paf.txt.
When you make software update, the .bin file of VRP5.1 should be upload on HD because of its size.
If these two files are missing, router will use the default license. This default license will limit the routing table to 100000 routes.
Those two files MUST uploaded on flash: not on hd. Copy this file olso on the slave SRU in order to have the same license on both SRU in case of switch after reboot.
Only after reboot and if the files are on the flash, the license will be activated.
Files should be transfered in ascii mode.
After software update, if you will copy the linse files in the same location wit vrp file (HDD) or you don't copy at all, after reboot the router will have the default license, not the license contained in the files.