BETTER HAVE THE NEW NRU 10 With the correct MAPS or you will have a long day......
DON'T PULL THE NVRAM CART unless you want to reprogramm it all........
BACK UP SYSTEM ...Pwr down, pull the software card 4.1)(leave in the NVRAM #1), put in new software card (6.1), power up and BACK UP SYS, Pwr down and replace the NVRAM (ver#2) with the 6.1 software, Pwr up and when stable reload thru the RAD all programming you backed up,