You were lucky.....
Not just new phones. I have (had) a second hand 4s. Last week Apple pushed out a "minor" update for a GPS issue - which has bricked my phone. Bit of research shows that I need the original factory fitted battery installed - bit of a problem as mine was replaced a couple of years ago. Even another Apple battery wouldn't get pass the error.
If I buy another 4s (since I have all the bits, a couple of paid apps, including a very nice case), I run the risk of another bricked phone. Shall I get a newer iPhone?
Screw that - I'm going to get a Android phone instead!!!