Update...
Working fine for 2 weeks and a few days. It appears that my system needed to be powered off and on after the upgrade. I assumed that the autorestart at the end of the install script would be enough. My system was a bit sluggish after the upgrade but was fine the next evening after being powered off for most of the day.
Looking back, I think the sluggishness was a result of a system freeze while I was backing up files to my USB devices before I downloaded and installed the new update. I should have powered off and on at that time, but I may have done a reset from the keyboard and continued on. In any case, I suspect my system was already compromised before I downloaded the new update.
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redfox
MicroA1-C
AmigaOS 4.1 Update 5