Ugh, it seems like every version bump for Android, I have a nightmare of a time trying to upgrade my phone. I try to keep the thing reasonably close to stock, but in this case I'd modified the build.prop file to do something as menial as change the DHCP hostname (seriously Google, what the fuck?). Unfortunately, I'd installed a build.prop editor rather than doing it via ADB, which made putting things back to stock harder than they should have been - but that's mostly my fault for not backing the thing up.
After much searching around, I couldn't find a clean copy of JDQ39's build.prop for takju, but I did find one for yakju. After grabbing it and doing a diff, I noticed that in my efforts to put things back I'd neglected to re-add a second newline at the end of the file.
Other than my phone's chronic inability to keep the 139MB update between attempts (which I later circumvented by copying it from /cache/cda87c8b9eebf8b1fd2b1d31757e542c4eafdb09.signed-takju-JWR66V-from-JDQ39.cda87c8b.zip to /sdcard/update.zip and using CWM to try install it), this was the only trouble I seemed to have this time around.
I really don't understand why a tech company as big as Google doesn't either a) let us change settings such as the above-mentioned hostname without resorting to root access or b) use something like FreeBSD's mergemaster to automagically massage changes into configuration files and then only panic when it fails, instead of expecting you not to touch a configuration file or to restore it back completely to stock (to the point of a hash matching, where a missing newline at the end of the file can break an update).
Oh well, now I see how long it takes for TRIM to do it's thing on Android, and see whether that helps performance or not. On first glance, it appears not to have clobbered my radio (which is still DVLH1, the Telstra radio from 4.1).