Actually, jetpack4.5.1 has been released for months. But I didn’t hear someone who just hit boot issue by pure jetpack + apt upgrade. Most of apt upgrade issue come from customization.
Also, I can confirm that we ran apt upgrade on our jetpack 4.5.1 when this release came out. And it didn’t hit error.
We will try to reproduce this issue with jetpack4.5.1 again. To save your time, please dump the serial console log when you hit issue.
Comparing why JP4.6 didn’t happen this issue is a little pointless. That question is more like why a new software release does not have a bug happened on old release.
And the reason is possibly a obvious one because it is called “new release”…