Here is what I did to compile 1.29:

tar xf busybox-1.22.1.tar.bz2
tar xf busybox-1.29.1.tar.bz2
cd busybox-1.22.1/configs
cp ~/develop/xiaofang/sdk/SN986_1.60_QR_Scan_019a_20160606_0951/snx_sdk/filesystem/busybox-1.22.1/src/configs/sn9866x_defconfig .
export PATH="/home/student/develop/xiaofang/sdk/SN986_1.60_QR_Scan_019a_20160606_0951/snx_sdk/toolchain/crosstool-4.5.2/bin:$PATH"
make CROSS_COMPILE=arm-linux- sn9866x_defconfig
cd ../busybox-1.29.1/
cp ../busybox-1.22.1/.config .
make CROSS_COMPILE=arm-linux- oldconfig
make CROSS_COMPILE=arm-linux- menuconfig
make CROSS_COMPILE=arm-linux- -j5
diff -ru busybox-1.22.1 ~/develop/xiaofang/sdk/SN986_1.50_P2P_TUTK_043a_20160308_1000/snx_sdk/filesystem/busybox-1.22.1/src/ > diff_1.22.1_snx.txt