diff --git a/tools/linux/maple_upload b/tools/linux/maple_upload
index 27359d2..e799f3a 100755
--- a/tools/linux/maple_upload
+++ b/tools/linux/maple_upload
@@ -26,15 +26,15 @@ DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
 # 750ms to 1500ms seems to work on my Mac
 
 
-${DIR}/upload-reset ${dummy_port_fullpath} 750
+"${DIR}/upload-reset" ${dummy_port_fullpath} 750
 
 
 #DFU_UTIL=$(dirname $0)/dfu-util/dfu-util
 DFU_UTIL=/usr/bin/dfu-util
 DFU_UTIL=${DIR}/dfu-util/dfu-util
-if [ ! -x ${DFU_UTIL} ]; then
+if [ ! -x "${DFU_UTIL}" ]; then
     echo "$0: error: cannot find ${DFU_UTIL}" >&2
     exit 2
 fi
 
-${DFU_UTIL} -d ${usbID} -a ${altID} -D ${binfile} ${dfuse_addr} -R
+"${DFU_UTIL}" -d ${usbID} -a ${altID} -D ${binfile} ${dfuse_addr} -R