Missing key or invalid release file?

[Jeffrey Walton <noloader@gmail.com>]

I'm having trouble installing a Sparc64 Chroot. The host system is
Debian Testing (not unstable).

I can't tell if the problem is a missing key or a missing release file.

Help would be appreciated.

*********

$ cat sparc.txt
 interpreter = /usr/bin/qemu-sparc-static
 interpreter = /usr/bin/qemu-sparc64-static
 interpreter = /usr/bin/qemu-sparc32plus-static


$ apt-get install debian-ports-archive-keyring
Reading package lists...
Building dependency tree...
Reading state information...
debian-ports-archive-keyring is already the newest version (2016.02.01).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


I: Running command: debootstrap --arch sparc64 --foreign --keyring
/usr/share/keyrings/debian-archive-keyring.gpg --variant=buildd
--exclude=debfoster unstable debian-sparc64
http://ftp.ports.debian.org/debian-ports/
I: Retrieving Release
I: Retrieving Release.gpg
I: Checking Release signature
E: Release signed by unknown key (key id B4C86482705A2CE1)


I: Running command: debootstrap --arch sparc64 --foreign --keyring
/usr/share/keyrings/debian-archive-keyring.gpg --variant=buildd
--exclude=debfoster unstable debian-sparc64
http://ftp.debian.org/debian
I: Retrieving Release
I: Retrieving Release.gpg
I: Checking Release signature
I: Valid Release signature (key id 126C0D24BD8A2942CC7DF8AC7638D0442B90D010)
E: Invalid Release file, no entry for main/binary-sparc64/Packages