Reading time: 1 min
Backup boot image:
dd if=/dev/block/platform/msm_sdcc.1/by-name/boot of=/sdcard/boot.img
# or using ADB with root shell:
adb shell dd if=/dev/block/platform/msm_sdcc.1/by-name/boot | dd of=./boot.img
Unpack Android boot image using Android Image Kitchen:
./unpackimg.sh boot.img
Extract config from vmlinuz (requires kernel with CONFIG_IKCONFIG_PROC=y):
$LINUX_KERNEL_SRC_DIR/scripts/extract-ikconfig ./vmlinuz