[Coco] 512K required for most Coco3 games?

[Steve C.]

Just received the wonderfully cool CocoSDC. It works fine, but...

Some .dsk images in the Coco3 folder won't mount properly. They show ?FS
ERROR when DIR is typed. Koronis1.dsk, for example, King's quest etc. I
tried writing a fresh downloaded copy from a few different sites with the
same results.

I have a stock 128K CC3. Do I need to a Cloud9 512K upgrade?