diff --git a/build-docker.sh b/build-docker.sh
index 0329819..b40d56d 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -8,7 +8,7 @@ DOCKER="docker"
 # Ensure that any config variables we passed in are written to an env_file
 # so invocations in subsquent shells preserve these values
 # Add || true so passing no custom vars doesn't bork up execution
-printenv | grep 'FWVERSION=\|SERIAL=\|ROOTUSER\|ROOTUSERPASS' || true > "$DIR/.customvars"
+printenv | grep -e FWVERSION -e SERIAL -e ROOTUSER -e ROOTUSERPASS || true > "$DIR/.customvars"
 
 if ! ${DOCKER} ps >/dev/null 2>&1; then
 	DOCKER="sudo docker"
diff --git a/export-image/prerun.sh b/export-image/prerun.sh
index a984c99..587d12a 100755
--- a/export-image/prerun.sh
+++ b/export-image/prerun.sh
@@ -39,8 +39,27 @@ BOOT_LENGTH=$(echo "$PARTED_OUT" | grep -e '^1:' | cut -d':' -f 4 | tr -d B)
 ROOT_OFFSET=$(echo "$PARTED_OUT" | grep -e '^2:' | cut -d':' -f 2 | tr -d B)
 ROOT_LENGTH=$(echo "$PARTED_OUT" | grep -e '^2:' | cut -d':' -f 4 | tr -d B)
 
+# Allow errors, losetup might fail the first time
+set +e
 BOOT_DEV=$(losetup --show -f -o "${BOOT_OFFSET}" --sizelimit "${BOOT_LENGTH}" "${IMG_FILE}")
+sleep 5
+set -e
+
+# Should work now
+BOOT_DEV=$(losetup --show -f -o "${BOOT_OFFSET}" --sizelimit "${BOOT_LENGTH}" "${IMG_FILE}")
+
+# Allow errors, losetup might fail the first time
+set +e
 ROOT_DEV=$(losetup --show -f -o "${ROOT_OFFSET}" --sizelimit "${ROOT_LENGTH}" "${IMG_FILE}")
+sleep 5
+set -e
+
+# Should work now
+ROOT_DEV=$(losetup --show -f -o "${ROOT_OFFSET}" --sizelimit "${ROOT_LENGTH}" "${IMG_FILE}")
+
+# Sleep for a bit for the mounted loop devices to show up
+sleep 5
+
 echo "/boot: offset $BOOT_OFFSET, length $BOOT_LENGTH"
 echo "/:     offset $ROOT_OFFSET, length $ROOT_LENGTH"
 
diff --git a/stage2/04-custom-tweaks/00-packages b/stage2/04-custom-tweaks/00-packages
index cfe86da..be6eb10 100644
--- a/stage2/04-custom-tweaks/00-packages
+++ b/stage2/04-custom-tweaks/00-packages
@@ -1 +1,3 @@
-python3-pip
\ No newline at end of file
+python3-pip
+v4l2loopback-dkms
+ffmpeg
\ No newline at end of file