USB key with -CURRENT, but /root not found on one laptop

[Hans Petter Selasky]

On Tuesday 21 April 2009, Matthias Apitz wrote:
> Hello,
>
> I've a boot-able USB key with -CURRENT from which I have booted and
> installed fine my small EeePC. I now wanted to update with the same
> procedure the laptop of my wife (which still runs RELENG_7) to make her
> happy access to the wonderful world of -CURRENT :-)
>
> the laptop itself can't boot from USB devices but there is still the old
> boot block on the disk which sees the USB as 'Drive 1' and offers to
> boot from by typing F5:
>
> F1: FreeBSD
> F5: Drive 1
>
> I typed F5
>
> this loads kernel /boot/kernel/kernel
> the kernel boots up fine ... until a message
>
> Trying to mount root from ufs:/dev/da0s1a
>
> Manual root filesystem specification:
>
>     <fstype>:<device> Mount <device> using filesystem <fstype>
>                       eg. ufs:da0s1a
>     ?                 List valid disk boot devices
>     <empty line>      Abort manual input
>
>
> [ an async message appears in this moment as ]
> [ da0: <Ut165 USB2FlashStorage 0.00> Removable Direct Access SCSI-2 device 
> ] [ da0: 40.000MB/s transfers ]
> [ da0: 7712MB (15794176 512 byte sectors: 255H 63 S/T 983C) ]
> [ this means that the running kernel has seen now the USB device at da0: ]
>
> typing ? gives:
>
> List of GEOM managed devices:
> ad4s1f ad4s1e ad4s1d ad4s1b ad4s1a ad4s1 ad4 acd0
>
> mountroot>
>
> typing at prompt mountroot>: ufs:da0s1a
>
> brings up menu again and again
>
> Why the kernel does not see da0s1a to mount the root filesystem?

There are some known issues in this area. I think Andrew Thompson is currently 
working on these issues.
 
--HPS