port-i386/41454: NetBSD on USB: root fails to be found

[nbsdold%gmx.net@localhost]

>Number:         41454
>Category:       port-i386
>Synopsis:       NetBSD on USB: root fails to be found
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 18 06:55:02 +0000 2009
>Originator:     Nino Ivanov
>Release:        5.0
>Organization:
>Environment:
(Just standard 5.0, no custom optimisations or recompilations.)
>Description:
Dear Sir or Madam,

I tried to install NetBSD 5 on a 2GB USB-stick, using the whole disk and not 
using an MBR. Installation always goes well, but booting under certain 
circumstances does not. I have on my machine OHCI as well as EHCI USB-ports, 
but as I don't know which is which, I cannot say where the failure occurs.

With a block size/fragment size 4096/512 on an FFSv1 file system, NetBSD fails 
to find its root partition when booting on one of the ports. It cannot be 
persuaded, either, because it does not allow booting from an sd* device (my 
case: sd0a). I see it boot, see green text as it detects my devices, then the 
usb-light turns off and I get a failure message that root could not be found.

On the other port, the USB-stick's light turns off for a moment, but just 
before the moment when I could get the failure message, the light turns on 
again, the text becomes white, and booting proceeds as it should.

Both ports can boot the stick if I install it with a block size/fragment size 
of 16k/2k. Again, the stick's light turns off for a moment, but turns on again, 
and booting proceeds normally.

I think I once or twice experienced something like this on 4.0.1 as well; but 
there, it was not the rule - sometimes it happened, sometimes it worked. And 
4.0.1 allowed manual setting of the sd*-device, while 5.0 doesn't.
>How-To-Repeat:
Install NetBSD on a 2GB stick with FFSv1 file system, using the whole disk and 
NOT with an MBR, and try to boot it on an EHCI or OHCI USB-port.
>Fix:
Use a larger block size and a larger fragment size for the FFSv1 file system. 
16k/2k works.

Alternatively, try setting manually the root device when NetBSD asks you - not 
always possible.