--- a/fontforge/cvundoes.c
+++ b/fontforge/cvundoes.c
@@ -3875,7 +3875,7 @@
 {
     int idx = 0;
     char filename[PATH_MAX];
-    snprintf(filename, PATH_MAX, "/tmp/fontforge-undo-to-string.sfd");
+    snprintf(filename, PATH_MAX, "@TERMUX_PREFIX@/tmp/fontforge-undo-to-string.sfd");
     FILE* f = fopen( filename, "w" );
     SFDDumpUndo( f, sc, undo, "Undo", idx );
     fclose(f);