A mate rang me this morning as he received some new sunrays to add to his fleet (good man) but they wouldn’t boot with the 27B error. This stumped him as he as 30 odd sunrays already in use and working fine. I noticed in his DHCP server options he was missing 2 settings I use.

066 and 049, these should both be pointed at your Sunray 3.1 Server, they are definitely needed if you are booting your DTU’s over a WAN but can be optional on a lan but as seen here it’s not set in stone that it will work without issue on the lan. Better safe then sorry in my book.