freebsd stable - Feb 2010 - kern/140661: [zfs] /boot/loader fails to work on a GPT/ZFS-only system on both 8.0-RC2 and RC3

> On Nov 18, 2009, at 21:57 , Scot Hetzel wrote:
> > Make sure you have LOADER_ZFS_SUPPORT in your /etc/src.conf:
> > 
> > dv8t01# cat /etc/src.conf
> > LOADER_ZFS_SUPPORT=YES
> 
> Ah! I also have LOADER_TFTP_SUPPORT=YES. Removing that, and everything
works.
> I don't know why I didn't think of that in the first place, but
maybe this
> is either a bug, or something that should be warned about when building
> loader(8)?
> 
> /Kenneth

I had the same problem which went away after removing TFTP support and
reinstalling the bootcode.
For now I suggest to add the following patch:

--- sys/boot/i386/loader/conf.c.orig	2010-02-13 14:08:31.154391969 +0000
+++ sys/boot/i386/loader/conf.c	2010-02-13 14:11:11.119255786 +0000
@@ -46,6 +46,10 @@
 #error "Cannot have both tftp and nfs support yet."
 #endif
 
+#if defined(LOADER_ZFS_SUPPORT) && defined(LOADER_TFTP_SUPPORT)
+#error "Cannot have both tftp and zfs support yet."
+#endif
+
 #if defined(LOADER_FIREWIRE_SUPPORT)
 extern struct devsw fwohci;
 #endif

I think having both options corrupt each other's environment 

system:

FreeBSD freebsd-master 8.0-STABLE FreeBSD 8.0-STABLE #2: Mon Jan 18 16:14:24 UTC
2010     root@freebsd-master:/usr/obj/usr/cvsup/8-stable/src/sys/VMWARE  amd64


Regards,
	Ruben