Firmware upgrade

[forexbob]

This may have been covered already but I couldn't find anything, so here goes...

Many moons ago I read many horror stories of upgrades gone bad and people losing their calculators. Every time I connect my Prime to the CK it asks me if I want to upgrade and I always decline, having those horror stories in the back of my mind.

So the question is: At this date, is the current firmware upgrade safe? I have but one Prime and can't afford another.

Thanks

Bob