[openwrt/openwrt] ipq40xx: sysupgrade: drop disabled UBI to UBI logic

[LEDE Commits]

chunkeey pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/8ac8c09f5ebbb6ae5e73b8a8ff4b095c1154f707

commit 8ac8c09f5ebbb6ae5e73b8a8ff4b095c1154f707
Author: Bjørn Mork <bjorn at mork.no>
AuthorDate: Sat Mar 20 11:48:27 2021 +0100

    ipq40xx: sysupgrade: drop disabled UBI to UBI logic
    
    The commented out code is not required, as the comment
    indicates.
    
    The purpose of this code seems to be to avoid issues caused
    by partially overwriting an existing UBI partition, where some
    of the erase counters would be reset but not the unmodified
    ones.  This problem has been solved in a more generic way by
    the UBI EOF marker. This ensures that any old PEBs after the
    marker are properly initialized.  It is therefore unnecessary
    to erase the whole partition before flashing a new OpenWrt
    factory image.
    
    Signed-off-by: Bjørn Mork <bjorn at mork.no>
---
 .../ipq40xx/base-files/lib/upgrade/linksys.sh      | 24 ++--------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh b/target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh
index de09d34aef..f1dc81f7c9 100755
--- a/target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh
+++ b/target/linux/ipq40xx/base-files/lib/upgrade/linksys.sh
@@ -47,10 +47,6 @@ linksys_get_target_firmware() {
 	esac
 }
 
-linksys_get_root_magic() {
-	(get_image "$@" | dd skip=786432 bs=4 count=1 | hexdump -v -n 4 -e '1/1 "%02x"') 2>/dev/null
-}
-
 platform_do_upgrade_linksys() {
 	local magic_long="$(get_magic_long "$1")"
 
@@ -100,23 +96,7 @@ platform_do_upgrade_linksys() {
 	}
 
 	[ "$magic_long" = "27051956" ] && {
-		# This magic is for a uImage (which is a sysupgrade image)
-		# check firmwares' rootfs types
-		local oldroot="$(linksys_get_root_magic "$target_mtd")"
-		local newroot="$(linksys_get_root_magic "$1")"
-
-		if [ "$newroot" = "55424923" ] && [ "$oldroot" = "55424923" ]; then
-			# we're upgrading from a firmware with UBI to one with UBI
-			# erase everything to be safe
-			# - Is that really needed? Won't remove (or comment) the if,
-			#   because it may be needed in a future device.
-			#mtd erase $part_label
-			#get_image "$1" | mtd -n write - $part_label
-			echo "writing \"$1\" UBI image to \"$part_label\" (UBI)..."
-			get_image "$1" | mtd write - "$part_label"
-		else
-			echo "writing \"$1\" image to \"$part_label\""
-			get_image "$1" | mtd write - "$part_label"
-		fi
+		echo "writing \"$1\" image to \"$part_label\""
+		get_image "$1" | mtd write - "$part_label"
 	}
 }