sdcard_image-rpi.bbclass: Fix error in conditional testdylan

When the shell tests for rootfs type I was seeing "[[: not found".  I
use echo and egrep to test for the xz rootfs type to work around this
error.

Signed-off-by: Seth Bollinger <seth.boll@gmail.com>
Signed-off-by: Andrei Gherzan <andrei@gherzan.ro>

1 files changed, 1 insertions, 1 deletions

diff --git a/classes/sdcard_image-rpi.bbclass b/classes/sdcard_image-rpi.bbclass
index 05087b5..a2fcd52 100644
--- a/classes/sdcard_image-rpi.bbclass
+++ b/classes/sdcard_image-rpi.bbclass
@@ -101,7 +101,7 @@ IMAGE_CMD_rpi-sdimg () {
         # Burn Partitions
         dd if=${WORKDIR}/boot.img of=${SDIMG} conv=notrunc seek=1 bs=$(expr ${IMAGE_ROOTFS_ALIGNMENT} \* 1024) && sync && sync
         # If SDIMG_ROOTFS_TYPE is a .xz file use xzcat
-        if [[ "$SDIMG_ROOTFS_TYPE" == *.xz ]]
+        if echo "${SDIMG_ROOTFS_TYPE}" | egrep -q "*\.xz"
         then
                 xzcat ${SDIMG_ROOTFS} | dd of=${SDIMG} conv=notrunc seek=1 bs=$(expr 1024 \* ${BOOT_SPACE_ALIGNED} + ${IMAGE_ROOTFS_ALIGNMENT} \* 1024) && sync && sync
         else