If you are compiling yocto for Raspberry Pi, there are chances you may see an error ( do_image_rpi_sdimg: Taskhash mismatch ) as below,
ERROR: rpi-hwup-image-1.0-r0 do_image_rpi_sdimg: Taskhash mismatch e7f72114a8e48d68bb5c66aebfc0126b verses f42bb303c421aa2770127fe4c480959b for /yocto/meta-raspberrypi/recipes-core/images/rpi-hwup-image.bb.do_image_rpi_sdimg
ERROR: Taskhash mismatch e7f72114a8e48d68bb5c66aebfc0126b verses f42bb303c421aa2770127fe4c480959b for /yocto/meta-raspberrypi/recipes-core/images/rpi-hwup-image.bb.do_image_rpi_sdimg
NOTE: Tasks Summary: Attempted 2133 tasks of which 2124 didnt need to be rerun and all succeeded.
Summary: There was 1 WARNING message shown.
Summary: There were 2 ERROR messages shown, returning a non-zero exit code.
Solution
$ vim meta-raspberrypi/classes/sdcard_image-rpi.bbclass
change following line from
IMAGE_CMD_rpi-sdimg[vardepsexclude] = "IMAGEDATESTAMP"
to
IMAGE_CMD_rpi-sdimg[vardepsexclude] = "${IMAGEDATESTAMP}"