Nokia-N900:~# apt-get install --reinstall kernel kernel-flasher fremantle-203-prReading package lists... Done
Building dependency tree
Reading state information... Done
Package kernel is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package kernel has no installation candidate

At this point a full reflash is clearly an option (and yes everything is backed up, and I've flashed a number of times before, so no big deal) .. but I was intrigued as to what went wrong.

I'm thinking the erroneous removal of mp-fremantle-203-pr was not great -- although kernel couldn't be found before this.

Am I missing a repo? Can someone check if this package is in their repo?