I have the same question.  I just bought a SLM2008, and have the 2.0.0.10 firmware.Whenever I would go into the web config, it would lock it up after navigating for a bit.  The problem was solved by running my ie in 64 bit mode.  I assuming some plugin or who knows what was the culprit...anyway...I wanted to upgrade the firmware to the lastest hoping to fix the IE issue and I saw that the newest firware was the v1.x that you mentioned.

I am curious as well as to why this is.  I can only speculate as to being related to the notorious bulging capacitors that affect the SLM and the other small business switches.  Perhaps they finally addressed it via a combination using quality (ie. non-Chineese) capacitors as well as some tweaks to the firmware.  Perhaps the newer firware would cause even more problems with the older SLM's (linksys and early Cisco branded, so they only have the v1.x available for download so someone with an older SLM doesn't install the firmware and cause even more problems.  People with the new fixed (God I hope it has been fixed) SLMs running v2.0.0.10 would see that their firmware is newer and not install it.  I guessing it's another way of them not publicly admitting to the known capacitor problem.