boot block differences between 4.x and 6.x ?

[M. Warner Losh]

In message: <43DF77B7.4050800 at samsco.org>
            Scott Long <scottl at samsco.org> writes:
: Luigi Rizzo wrote:
: > maybe some of you know the answer here...
: > 
: > the revised picobsd script (attached here, it uses
: > sysutils/makefs instead of vnconfig/mdconfig so it can
: > run as a non privileged user) that i was using to
: > create images with the 4.11 boot blocks (boot1 and boot2),
: > does not seem to work anymore with the boot blocks
: > taken from 6.0 (and so, -current as well).
: > 
: > When i force it to use the 4.x boot blocks, all is fine,
: > and the picobsd.bin produced (built on 6.0 using 7-current
: > sources) boots fine on qemu.
: > 
: > I am a bit puzzled on what could be the relevant change in boot1/boot2
: > could have caused the loss of functionality.
: > 
: > If that matters, picobsd bypasses /boot/loader and goes straight
: > to boot /kernel (the name is patched into the boot block,
: > but it does not matter because the new blocks do not
: > even get to the point of showing the 'missing /boot/loader'
: > error message).
: > 
: > does anyone know where should i look at ?
: > 
: > 	thanks
: > 	luigi
: > 
: 
: The big difference is that the boot blocks grew significantly to
: support UFS2.

And boot1/boot2 were merged into boot...

Warner