I wrote:
> Then I did
>
> # fsysopts /install --readonly
>
> with no such assertion failure, and the stream of set_hyper messages
> ended with
>
> ext2fs: /dev/hd0s5: warning: finished set_hyper(0,0) 1 => 0x1
>
> (note 0x1).
whoops, that should have been
ext2fs: /dev/hd0s5: warning: set_hyper(1,1) 1 => 0
ext2fs: /dev/hd0s5: warning: finished set_hyper(1,1) 1 => 0x1
hope this is enough "legwork" :-)