diff --git a/variants/windows/pydevices/mpconfigvariant.h b/variants/windows/pydevices/mpconfigvariant.h
index a5ffe18..8d8d813 100644
--- a/variants/windows/pydevices/mpconfigvariant.h
+++ b/variants/windows/pydevices/mpconfigvariant.h
@@ -3,3 +3,7 @@
 // -X heapsize= still overrides it. Needs patch 0012.
 #include "variants/dev/mpconfigvariant.h"
 #define MICROPY_UNIX_DEFAULT_HEAP_SIZE (8 * 1024 * 1024)
+// Run a built-in module's __init__ on import, as unix does. The windows port
+// sits at the core ROM level, where this is off, so `import jpegio` after
+// lv.init() never registered displayif's LVGL decoder (displayif#41).
+#define MICROPY_MODULE_BUILTIN_INIT (1)