After 6 months, finally decided to try SVA1000X_V3.2.2.5.0.ADS on an updated SSA3021X+ that System Info said was SVA1032X, 3.2.2.4.0.r2
Everything went fine, cal files still work, 10,001 points on VNA, etc. Only curious thing I haven't seen posted is the sw1 reports as: 3.2.2.5.0.r8 , don't remember others having the r8?
The update took < 2 minutes and rebooted 2 or 3 times. Seemed to work correctly without another manual restart but I did one anyway after a little tinkering.
Perhaps the thumb drive used makes a difference on success. I used an old 256M fat16 drive. The drive had 75 other files and folders so it doesn't need to be empty.