This doesn't happen on amd64. Do you also have to re-run mkswap when switching back to the older, working kernel, or does simply using the other kernel let you run swapon on the same file that doesn't work with the newer kernel?
This doesn't happen on amd64. Do you also have to re-run mkswap when switching back to the older, working kernel, or does simply using the other kernel let you run swapon on the same file that doesn't work with the newer kernel?