diff --git a/src/util/genfsimg b/src/util/genfsimg
index 875815037..84deea42b 100755
--- a/src/util/genfsimg
+++ b/src/util/genfsimg
@@ -312,7 +312,6 @@ fi
 if [ -n "${FATIMG}" ] ; then
     FATSIZE=$(du -s -k "${FATDIR}" | cut -f1)
     FATSIZE=$(( FATSIZE + PAD + 256 ))
-    touch "${FATIMG}"
     if [ "${FATSIZE}" -le "1440" ] ; then
 	FATSIZE=1440
 	FATARGS="-f 1440"
@@ -325,6 +324,8 @@ if [ -n "${FATIMG}" ] ; then
 	FATSERIAL=$(( SOURCE_DATE_EPOCH % 100000000 ))
 	FATARGS="${FATARGS} -N ${FATSERIAL}"
     fi
+    touch "${FATIMG}"
+    truncate -s 0 "${FATIMG}"
     truncate -s "${FATSIZE}K" "${FATIMG}"
     mformat -v iPXE -i "${FATIMG}" ${FATARGS} ::
     mcopy -i "${FATIMG}" -s "${FATDIR}"/* ::