The extensible SDK tarballs for x86_64 are in http://autobuilder.yoctoproject.org/pub/releases/yocto-2.1_M2.rc1/toolchain/x86_64/ : poky-glibc-x86_64-core-image-minimal-aarch64-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 07:36 1.6G poky-glibc-x86_64-core-image-minimal-armv5e-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 04:15 1.6G poky-glibc-x86_64-core-image-minimal-armv7a-neon-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 06:01 1.4G poky-glibc-x86_64-core-image-minimal-core2-64-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 04:29 1.8G poky-glibc-x86_64-core-image-minimal-i586-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 07:19 1.7G poky-glibc-x86_64-core-image-minimal-mips32r2-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 07:46 1.6G poky-glibc-x86_64-core-image-minimal-mips64-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 08:39 1.7G poky-glibc-x86_64-core-image-minimal-ppc7400-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 04:17 1.7G poky-glibc-x86_64-core-image-minimal-ppce500v2-toolchain-ext-2.0+snapshot.sh 27-Jan-2016 04:32 1.5G But in i686 directory, there are no sdk_ext tarballs for i686.
When building the ext_sdk we can only build it for the native architecture due to it reusing the native sstate via uninative. Since we don't have 32 bit builders, we can't build 32 bit ext_sdk so at least for now, this configuration isn't supported.