diff --git a/assets/start-psiphon b/assets/start-psiphon
index 8b43ccd..6cc47f9 100644
--- a/assets/start-psiphon
+++ b/assets/start-psiphon
@@ -20,7 +20,7 @@ if [ ! -f /config/psiphon.config ]; then
         sed -i -E 's/"EgressRegion"[[:space:]]*:[[:space:]]*"[^"]*"/"EgressRegion": "'${EGRESS_REGION}'"/' /config/psiphon.config
     fi
     if [ -n "${UPSTREAM_PROXY}" ]; then
-        sed -i -E 's/"UpstreamProxyUrl"[[:space:]]*:[[:space:]]*"[^"]*"/"UpstreamProxyUrl": "'"${UPSTREAM_PROXY}"'"/' /config/psiphon.config
+        sed -i -E 's|"UpstreamProxyUrl"[[:space:]]*:[[:space:]]*"[^"]*"|"UpstreamProxyUrl": "'${UPSTREAM_PROXY}'"|' /config/psiphon.config
     fi
 fi
 
@@ -46,4 +46,4 @@ chown -R psiphon:psiphon /config
 
 su -s /bin/sh psiphon <<EOF
 psiphon -config /config/psiphon.config
-EOF
\ No newline at end of file
+EOF