[openwrt/openwrt] uboot-envtools: mediatek_filogic: fix BPi-R3 when no OS is installed

[LEDE Commits]

dangole pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/f46355b4d7d42bcd365bc642048ac3614b76cce9

commit f46355b4d7d42bcd365bc642048ac3614b76cce9
Author: Daniel Golle <daniel at makrotopia.org>
AuthorDate: Tue Oct 18 20:01:23 2022 +0100

    uboot-envtools: mediatek_filogic: fix BPi-R3 when no OS is installed
    
    Fix accessing the environment in case no OS is installed on the flash
    media selected for boot as this is possible when booting initramfs.
    In case of relying on the device specified to be mounted as rootfs to
    be present, rather just use the kernel cmdline 'root' variable as a
    hint to decide where to read/write the U-Boot environment.
    
    Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 package/boot/uboot-envtools/files/mediatek_filogic | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/package/boot/uboot-envtools/files/mediatek_filogic b/package/boot/uboot-envtools/files/mediatek_filogic
index a82f140a6e..a29ec7d0ee 100644
--- a/package/boot/uboot-envtools/files/mediatek_filogic
+++ b/package/boot/uboot-envtools/files/mediatek_filogic
@@ -13,21 +13,18 @@ board=$(board_name)
 
 case "$board" in
 bananapi,bpi-r3)
-	. /lib/upgrade/common.sh
-	export_bootdevice
-	export_partdevice rootdev 0
-	case "$rootdev" in
-	mmc*)
+	case "$(cmdline_get_var root)" in
+	/dev/mmc*)
 		local envdev=$(find_mmc_part "ubootenv" $rootdev)
 		ubootenv_add_uci_config "$envdev" "0x0" "0x40000" "0x40000" "1"
 		ubootenv_add_uci_config "$envdev" "0x40000" "0x40000" "0x40000" "1"
 		;;
-	mtd*)
+	/dev/mtd*)
 		local envdev=/dev/mtd$(find_mtd_index "u-boot-env")
 		ubootenv_add_uci_config "$envdev" "0x0" "0x20000" "0x20000" "1"
 		ubootenv_add_uci_config "$envdev" "0x20000" "0x20000" "0x20000" "1"
 		;;
-	*)
+	/dev/ubi*)
 		. /lib/upgrade/nand.sh
 		local envubi=$(nand_find_ubi ubi)
 		local envdev=/dev/$(nand_find_volume $envubi ubootenv)