sysupgrade: adjust get_flash_type function

general/overlay/usr/sbin/sysupgrade

@@ -1,9 +1,9 @@
 #!/bin/sh
 #
-# OpenIPC.org | v.20221118
+# OpenIPC.org | v.20230503
 #
 
-scr_version=1.0.16
+scr_version=1.0.17
 
 args=" $@"
 
@@ -65,7 +65,7 @@ do_update_rootfs() {
 		check_soc "$(head -1 ${y}/etc/hostname | cut -d- -f2)"
 		compare_versions "$system_version" "$(get_system_version "$y")" && exit_update=1
 		umount "$y" && rm -rf "$y" && losetup -d "$loop"
-		[ "$exit_update" ] && return 0
+		[ "1" = "$exit_update" ] && return 0
 	else
 		die "Unable to mount $y!"
 	fi
@@ -77,15 +77,14 @@ do_update_rootfs() {
 do_wipe_overlay() {
 	echo_c 33 "\nOverlayFS"
 	echo "Erase overlay partition"
-	[ $(ipcinfo -F) = "nand" ] || jffs2="-j"
+	[ $(get_flash_type mtd) = "nand" ] || jffs2="-j"
 	flash_eraseall $jffs2 "$(get_device "rootfs_data")"
 }
 
 download_firmware() {
 	echo_c 33 "\nFirmware"
 	osr=$(get_system_build)
-	ftype=$(ipcinfo -F 2>/dev/null)
-	[ ${#ftype} -ge 4 ] && ftype=$(get_flash_type)
+	ftype=$(get_flash_type)
 	build="${soc}-${ftype}-${osr}"
 	[ -z "$url" ] && url="https://github.com/OpenIPC/firmware/releases/download/latest/openipc.${build}.tgz"
 	echo "Download from $url"
@@ -206,10 +205,10 @@ get_system_build() {
 	grep "BUILD_OPTION" "/etc/os-release" | head -1 | cut -d= -f2
 }
 
-# This flash type detection is deprecated and will be removed in the next updates...
 get_flash_type() {
-  has_nand=$(fw_printenv bootcmd | grep nand | wc -l)
-  [ "1" = "$has_nand" ] && echo "nand" || echo "nor"
+	local x=$(ipcinfo -F)
+	[ -z "$1" ] && [ "$x" = "nand" ] && $(fw_printenv bootcmd | grep -qv nand) && x=nor
+	echo "$x"
 }
 
 print_sysinfo() {