diff --git a/ports/zephyr-cp/boards/nordic/nrf54l15tag/circuitpython.toml b/ports/zephyr-cp/boards/nordic/nrf54l15tag/circuitpython.toml
index 1e31efd1a62..90ca03486c4 100644
--- a/ports/zephyr-cp/boards/nordic/nrf54l15tag/circuitpython.toml
+++ b/ports/zephyr-cp/boards/nordic/nrf54l15tag/circuitpython.toml
@@ -1,4 +1,6 @@
 CIRCUITPY_BUILD_EXTENSIONS = ["hex"]
+# The ru build had only 8 bytes of flash left.
+DISABLED_MODULES = ["msgpack"]
 
 # QFN48 package pin numbers.
 [pins]