diff --git a/package/base-files/files/lib/upgrade/common.sh b/package/base-files/files/lib/upgrade/common.sh
index ef7ce57e7e..018cc72f47 100644
--- a/package/base-files/files/lib/upgrade/common.sh
+++ b/package/base-files/files/lib/upgrade/common.sh
@@ -103,16 +103,23 @@ rootfs_type() {
 	mount | awk '($3 ~ /^\/$/) && ($5 !~ /rootfs/) { print $5 }'
 }
 
-get_image() {
+get_image() { # <source> [ <command> ]
 	local from="$1"
-	local conc="cat"
+	local cmd="$2"
+	local conc
 
-	[ "$GZIPED" -eq 1 ] && conc="zcat"
+	if [ -z "$cmd" ]; then
+		case "$from" in
+			http://*|ftp://*) cmd="wget -O- -q";;
+			*) cmd="cat";;
+		esac
+		local magic="$(eval $cmd $from | dd bs=2 count=1 2>/dev/null | hexdump -n 2 -e '1/1 "%02x"')"
+		case "$magic" in
+			1f8b) conc="| zcat";;
+		esac
+	fi
 
-	case "$from" in
-		http://*|ftp://*) wget -O- -q "$from" | "$conc";;
-		*) cat "$from" | "$conc";;
-	esac
+	eval "$cmd $from $conc"
 }
 
 get_magic_word() {
diff --git a/package/base-files/files/sbin/sysupgrade b/package/base-files/files/sbin/sysupgrade
index ecc5e9a708..f25195a520 100755
--- a/package/base-files/files/sbin/sysupgrade
+++ b/package/base-files/files/sbin/sysupgrade
@@ -9,7 +9,6 @@ export VERBOSE=1
 export SAVE_CONFIG=1
 export DELAY=
 export CONF_IMAGE=
-export GZIPED=0
 # parse options
 while [ -n "$1" ]; do 
 	case "$1" in
@@ -19,7 +18,6 @@ while [ -n "$1" ]; do
 		-q) export VERBOSE="$(($VERBOSE - 1))";;
 		-n) export SAVE_CONFIG=0;;
 		-f) export CONF_IMAGE="$2"; shift;;
-		-g) export GZIPED=1;;
 		-*)
 			echo "Invalid option: $1"
 			exit 1
@@ -42,7 +40,6 @@ Usage: $0 [options] <image file or URL>
 Options:
 	-d <delay>   add a delay before rebooting
 	-f <config>  restore configuration from .tar.gz (file or url)
-	-g           gziped image
 	-i           interactive mode
 	-n	     do not save configuration over reflash
 	-q           less verbose
@@ -99,7 +96,7 @@ if [ -n "$CONF_IMAGE" ]; then
 			exit 1
 		;;
 	esac
-	get_image "$CONF_IMAGE" > "$CONF_TAR"
+	get_image "$CONF_IMAGE" "cat" > "$CONF_TAR"
 	export SAVE_CONFIG=1
 elif ask_bool $SAVE_CONFIG "Keep config files over reflash"; then
 	do_save_conffiles