[openwrt/openwrt] base-files: stage2: add 'tail' to sysupgrade environment

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch openwrt-22.03:
https://git.openwrt.org/4bda308657bb39f3ad4a0d294a89ac867b8801a7

commit 4bda308657bb39f3ad4a0d294a89ac867b8801a7
Author: Tony Ambardar <itugrok at yahoo.com>
AuthorDate: Fri Dec 2 23:13:22 2022 -0800

    base-files: stage2: add 'tail' to sysupgrade environment
    
    This is used to access footer data in firmare files, and is simpler and
    less error-prone than using 'dd' with calculated offsets.
    
    Signed-off-by: Tony Ambardar <itugrok at yahoo.com>
    (cherry picked from commit 9cbc825b30a60c4c4b466301b87e15e59b107f24)
---
 package/base-files/files/lib/upgrade/stage2 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/base-files/files/lib/upgrade/stage2 b/package/base-files/files/lib/upgrade/stage2
index 5e0d73631b..0c1ffb5144 100755
--- a/package/base-files/files/lib/upgrade/stage2
+++ b/package/base-files/files/lib/upgrade/stage2
@@ -41,7 +41,7 @@ switch_to_ramfs() {
 		pivot_root mount_root reboot sync kill sleep		\
 		md5sum hexdump cat zcat dd tar				\
 		ls basename find cp mv rm mkdir rmdir mknod touch chmod \
-		'[' printf wc grep awk sed cut				\
+		'[' printf wc grep awk sed cut tail			\
 		mtd partx losetup mkfs.ext4 nandwrite flash_erase	\
 		ubiupdatevol ubiattach ubiblock ubiformat		\
 		ubidetach ubirsvol ubirmvol ubimkvol			\