I tried building first from an old version of 2.1 on flatfish. It gave me an error about my tablet not having the Bluetooth files which it was trying to adb pull , which means it expected every build to have them ?
I wouldn’t call https://bugzilla.mozilla.org/show_bug.cgi?id=1098569 as a bug as the newer build has this bluetooth issue solved.
The build went on smoothly but is stopping at libvpx .I tried removing objdir gecko and out and rebuilt for no use . It stops at libvpx. 
I believe you need to flash this build first to get those Bluetooth files onto the tablet, then it will successfully pull all of the required files.
Yes I understood . Sorry for confusing you all by telling entire story .
cd mangle; make libs
vp8_shortwalsh4x4_neon.o
../../../gecko/media/libvpx/vp8/encoder/arm/neon/vp8_shortwalsh4x4_neon.c: In function 'vp8_short_walsh4x4_neon':
../../../gecko/media/libvpx/vp8/encoder/arm/neon/vp8_shortwalsh4x4_neon.c:118:1: internal compiler error: in trunc_int_for_mode, at explow.c:56
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
In the directory /home/someuser/b2g_flatfish/objdir-gecko/media/libvpx
The following command failed to execute properly:
/usr/bin/ccache /home/someuser/b2g_flatfish/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.6/bin/arm-linux-androideabi-gcc -o vp8_shortwalsh4x4_neon.o -c -I../../dist/system_wrappers -include /home/someuser/b2g_flatfish/gecko/config/gcc_hidden_dso_handle.h -DHAVE_CONFIG_H=vpx_config.h -D__linux__ -DAB_CD=en-US -DNO_NSPR_10_SUPPORT -I/home/someuser/b2g_flatfish/gecko/media/libvpx -I. -I/home/someuser/b2g_flatfish/ndk/sources/android/cpufeatures -I../../dist/include -I/home/someuser/b2g_flatfish/objdir-gecko/dist/include/nspr -I/home/someuser/b2g_flatfish/objdir-gecko/dist/include/nss -fPIC -DANDROID -isystem /home/someuser/b2g_flatfish/bionic/libc/arch-arm/include -isystem /home/someuser/b2g_flatfish/bionic/libc/include/ -isystem /home/someuser/b2g_flatfish/bionic/libc/kernel/common -isystem /home/someuser/b2g_flatfish/bionic/libc/kernel/arch-arm -isystem /home/someuser/b2g_flatfish/bionic/libm/include -I/home/someuser/b2g_flatfish/system -I/home/someuser/b2g_flatfish/system/core/include -isystem /home/someuser/b2g_flatfish/bionic -I/home/someuser/b2g_flatfish/
hardware/libhardware/include -I/home/someuser/b2g_flatfish/external/valgrind/fxos-include -I/home/someuser/b2g_flatfish/frameworks/native/include -I/home/someuser/b2g_flatfish/frameworks/av/include -I/home/someuser/b2g_flatfish/frameworks/av/include/media -I/home/someuser/b2g_flatfish/frameworks/av/include/camera -I/home/someuser/b2g_flatfish/frameworks/native/include/media/openmax -I/home/someuser/b2g_flatfish/frameworks/av/media/libstagefright/include -include ../../mozilla-config.h -DMOZILLA_CLIENT -MD -MP -MF .deps/vp8_shortwalsh4x4_neon.o.pp -DANDROID -isystem /home/someuser/b2g_flatfish/bionic/libc/arch-arm/include -isystem /home/someuser/b2g_flatfish/bionic/libc/include/ -isystem /home/someuser/b2g_flatfish/bionic/libc/kernel/common -isystem /home/someuser/b2g_flatfish/bionic/libc/kernel/arch-arm -isystem /home/someuser/b2g_flatfish/bionic/libm/include -I/home/someuser/b2g_flatfish/system -I/home/someuser/b2g_flatfish/system/core/include -isystem /home/someuser/b2g_flatfish/bionic -I/home/someuser/b2g_flatfish/hardware/libhardware/include -I/home/someuser/b2g_flatfish/
external/valgrind/fxos-include -I/home/someuser/b2g_flatfish/frameworks/native/include -I/home/someuser/b2g_flatfish/frameworks/av/include -I/home/someuser/b2g_flatfish/frameworks/av/include/media -I/home/someuser/b2g_flatfish/frameworks/av/include/camera -I/home/someuser/b2g_flatfish/frameworks/native/include/media/openmax -I/home/someuser/b2g_flatfish/frameworks/av/media/libstagefright/include -Wall -Wdeclaration-after-statement -Wempty-body -Wpointer-to-int-cast -Wsign-compare -Wtype-limits -Wno-unused -mandroid -fno-short-enums -fno-exceptions -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=softfp -std=gnu99 -fgnu89-inline -fno-strict-aliasing -ffunction-sections -fdata-sections -fno-math-errno -pipe -DNDEBUG -DTRIMMED -g -freorder-blocks -Os -fno-reorder-functions -funwind-tables -Wno-sign-compare -march=armv7-a -mthumb -mfloat-abi=softfp -mfpu=neon /home/someuser/b2g_flatfish/gecko/media/libvpx/vp8/encoder/arm/neon/vp8_shortwalsh4x4_neon.c
make[6]: *** [vp8_shortwalsh4x4_neon.o] Error 1
make[5]: *** [media/libvpx/target] Error 2
make[4]: *** [compile] Error 2
make[3]: *** [default] Error 2
make[2]: *** [realbuild] Error 2
make[1]: *** [build] Error 2
make: *** [out/target/product/flatfish/obj/DATA/gecko_intermediates/gecko] Error 2Oh, I see. There is a bug filed for that issue and there’s a patch which I have tested (comment 16) and works.
Why do not pull this patch into the source code?
Is there any problem in this patch?
Thanks.
It’s just been pulled into b2g, the bug is resolved.