diff --git a/update-notify b/update-notify
index 851e62b..ed7a8b6 100755
--- a/update-notify
+++ b/update-notify
@@ -15,6 +15,7 @@ declare -A KERNELS=(
 state_dir="${XDG_STATE_HOME:-$HOME/.local/state}/update-notify"
 
 [[ $threshold =~ ^[0-9]+$ ]] || { echo "Threshold must be a number" >&2; exit 1; }
+threshold=$((10#$threshold))  # force base 10, so e.g. "08" isn't read as octal
 mkdir -p "$state_dir"
 
 # notify-send from cron/systemd needs the session bus address
@@ -137,8 +138,7 @@ if (( over_threshold )); then
     # fwupdmgr get-updates exits 0 when updates are available, 2 when there are none.
     # --no-metadata-check avoids prompting/refreshing; the fwupd-refresh timer keeps metadata fresh.
     if command -v fwupdmgr >/dev/null 2>&1; then
-        timeout 30 fwupdmgr get-updates --no-metadata-check </dev/null >/dev/null 2>&1
-        if (( $? == 0 )); then
+        if timeout 30 fwupdmgr get-updates --no-metadata-check </dev/null >/dev/null 2>&1; then
             reminders+=("fwupdmgr (firmware updates available)")
         fi
     fi