This is a nit, but might confuse a newbie. :-) When probing for a DEC TGA it does find it, but the text for the probing mentions the DEC TGA as a 21040 chip. This is incorrect. The chip is a 21030. The 21040 is an ethernet chip and this might possibly confuse someone new to Alpha/Linux. In any case it's a typo and I assume the text is in Xconfigurator in the probe code.
Just a quick addendum...you may need to update the new graphical install package for 6.1 too. I haven't seen the new installer but I'm sure there is some type of X configurator and the typo may have carried over.
The pcitable was rewritten for 6.1. Please make sure it's correct there.