Though a page exists for "How to add VGA Adaptor", I am creating a new page, since I have tried the exixting method and found it is obsolete and no more supported.
This "How-to" will help you to compile a new firmware and add VGA Adaptor.
I explain here the methods I have followed to do the same.
I have setup the openembedded build environment
Then, bitbake slugos-image downloaded and built upslug2
Once this is done, Connected the NSLU2 to my PC by peer-to-peer to avoid our LAN network congestion Set my IP- to 18.104.22.168
Booted the NSLU2 in Upgrade Mode. Ran upslug2.
Then upslug2 --target="XX:XX:XX:XX:XX:XX" --image="/path/to/tmp/deply/image/slugos-image.bin"
This will flash your existing firmware with the one you have built.
You can enable the build the sis