diff --git a/platform/kindle/koreader.sh b/platform/kindle/koreader.sh
index 0d3d375ef..3d79bd533 100755
--- a/platform/kindle/koreader.sh
+++ b/platform/kindle/koreader.sh
@@ -113,6 +113,7 @@ if [ -f "${NEWUPDATE}" ]; then
         logmsg "Update failed :("
         eips_print_bottom_centered "Update failed :(" 1
     fi
+    rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
 fi
 
 # load our own shared libraries if possible
diff --git a/platform/kobo/koreader.sh b/platform/kobo/koreader.sh
index 48de15e8e..8bcfceffc 100755
--- a/platform/kobo/koreader.sh
+++ b/platform/kobo/koreader.sh
@@ -12,7 +12,9 @@ NEWUPDATE="${KOREADER_DIR}/ota/koreader.updated.tar"
 INSTALLED="${KOREADER_DIR}/ota/koreader.installed.tar"
 if [ -f "${NEWUPDATE}" ]; then
     # TODO: any graphic indication for the updating progress?
-    ./tar xf "${NEWUPDATE}" --strip-components=1 --no-same-permissions --no-same-owner && mv "${NEWUPDATE}" "${INSTALLED}"
+    ./tar xf "${NEWUPDATE}" --strip-components=1 --no-same-permissions --no-same-owner \
+        && mv "${NEWUPDATE}" "${INSTALLED}"
+    rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
 fi
 
 # load our own shared libraries if possible
diff --git a/platform/pocketbook/koreader.app b/platform/pocketbook/koreader.app
index 17f90db92..aa4e9e6f4 100755
--- a/platform/pocketbook/koreader.app
+++ b/platform/pocketbook/koreader.app
@@ -7,9 +7,11 @@ KOREADER_DIR=/mnt/ext1/applications/koreader
 # update to new version from OTA directory
 NEWUPDATE="${KOREADER_DIR}/ota/koreader.updated.tar"
 INSTALLED="${KOREADER_DIR}/ota/koreader.installed.tar"
-if [ -f ${NEWUPDATE} ]; then
+if [ -f "${NEWUPDATE}" ]; then
     # TODO: any graphic indication for the updating progress?
-    cd /mnt/ext1/ && tar xf ${NEWUPDATE} && mv ${NEWUPDATE} ${INSTALLED}
+    cd /mnt/ext1/ && tar xf "${NEWUPDATE}" --no-same-permissions --no-same-owner \
+        && mv "${NEWUPDATE}" "${INSTALLED}"
+    rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
 fi
 
 # we're always starting from our working directory
diff --git a/platform/ubuntu-touch/koreader.sh b/platform/ubuntu-touch/koreader.sh
index 3c5e5efd2..350ed78c0 100755
--- a/platform/ubuntu-touch/koreader.sh
+++ b/platform/ubuntu-touch/koreader.sh
@@ -9,7 +9,9 @@ NEWUPDATE="${KOREADER_DIR}/ota/koreader.updated.tar"
 INSTALLED="${KOREADER_DIR}/ota/koreader.installed.tar"
 if [ -f "${NEWUPDATE}" ]; then
     # TODO: any graphic indication for the updating progress?
-    cd .. && tar xf "${NEWUPDATE}" && mv "${NEWUPDATE}" "${INSTALLED}"
+    cd .. && tar xf "${NEWUPDATE}" --no-same-owner --no-same-permissions \
+        && mv "${NEWUPDATE}" "${INSTALLED}"
+    rm -f "${NEWUPDATE}" # always purge newupdate in all cases to prevent update loop
 fi
 
 # we're always starting from our working directory