diff --git a/package/block-mount/files/50_determine_usb_root b/package/block-mount/files/50_determine_usb_root
index 8c5841e32..d39806266 100644
--- a/package/block-mount/files/50_determine_usb_root
+++ b/package/block-mount/files/50_determine_usb_root
@@ -9,6 +9,8 @@ determine_external_root() {
 	pi_include /lib/functions/mount.sh
 
 	local OLD_UCI_CONFIG_DIR="$UCI_CONFIG_DIR"
+	local OLD_PATH="$PATH"
+	local OLD_LD_LIBRARY_PATH="$LD_LIBRARY_PATH"
 	set_jffs_mp
 	determine_root_device
 
@@ -19,6 +21,9 @@ determine_external_root() {
 		UCI_CONFIG_DIR="/tmp/overlay/etc/config"
 		ER_IS_SQUASHFS=true
 		ER_OVERLAY_PREFIX="/tmp/overlay"
+		PATH=$ER_OVERLAY_PREFIX/sbin:$PATH
+		LD_LIBRARY_PATH=$ER_OVERLAY_PREFIX/usr/lib:$LD_LIBRARY_PATH
+		export PATH LD_LIBRARY_PATH
 	fi
 
 	# For squashfs on firstboot root_device will be tmpfs for the ramoverlay,
@@ -51,6 +56,9 @@ determine_external_root() {
 		}
 	}
 	UCI_CONFIG_DIR="$OLD_UCI_CONFIG_DIR"
+	PATH="$OLD_PATH"
+	LD_LIBRARY_PATH="$OLD_LD_LIBRARY_PATH"
+	export PATH LD_LIBRARY_PATH
 }
 
 boot_hook_add preinit_mount_root determine_external_root