I fell into this trap as well. My phone's product code (050L3S6) never gets updates fast enough and only accepts the cmt-mcusw portion of the flash from very specific regions only (I wrote about it here some time ago: http://forum.meego.com/showthread.php?t=4728&page=15).

That being said, I used the new NSS (pro?) to change my product code, not realizing the bugger also changed my hw code to the same value. After saving the changes, I was unable to flash any image at all and nearly threw the handset out the bloody window. I found that by using the kernel and initrd from here: http://wiki.meego.com/N950/Fixing_MALF_state I could boot into a state where I could use NSS and NSS(pro) to fix the hw code and product code. Hopefully I won't ever have to flash again.. It's a proverbial detective novel each time.