I wasn't sure what the right place for this question was: feel free to move it.

Adobe has released a major security fix for Flash Player since the version on my N800. The flaw they fixed allows malicious web pages to run arbitrary code on any machine that visits them. The vulnerability does affect Linux, though of course the payloads are almost certain to be Windows-specific.

As a matter of principle I'd like to upgrade.

Application Manager doesn't list the Flash plug-in as one of the things it can control. The Plug-in item on the Web Tools menu allows enabling and disabling it but no other control. Adobe's page doesn't have a .deb package. I could try to find it in the file system, but I'd be terrified of breaking something if I tried a manual removal and replacement.

In general, is there an equivalent on this device to the routine apt-get update and apt-get upgrade?

Nifty machine, by the way! It's a qualitative change to have Internet in my pocket at all times.