debootstrap cannot create bootstraps on certain types of Opteron processors

On systems affected by this libc6 bug (https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/956051) there seems to be no way to use debootstrap to successfully make a precise environment:

debootstrap --arch amd64 precise test
I: Retrieving Release
I: Retrieving Release.gpg
I: Checking Release signature

<normal output snipped>

I: Installing core packages...
W: Failure trying to run: chroot /mnt/test dpkg --force-depends --install /var/cache/apt/archives/debconf_1.5.42ubuntu1_all.deb

The following shows up in the dmesg on the host:

[261139.291434] pycompile[30582] trap invalid opcode ip:7f48532cae11 sp:7fff0400e7e0 error:0 in libm-2.15.so[7f4853288000+f9000]

This is because debootstrap does not use or understand the usage of *-updates, so the older libc is used (which triggers the bug).

Way to replicate the issue:

Install 12.04 on a newer Opteron (mine is a 6348)
Install xen-hypervisor-4.1-amd64, xen-tools
try to use debootstrap / xen-create-image
both fail and leave "invalid opcode" messages in dmesg

I'm not sure where to open a bug about this, because the issue is really that the bugfix for libc6 needs to be pushed to precise, and not precise-updates.