diff --git a/procedures/phal/set_SPI_mux.cpp b/procedures/phal/set_SPI_mux.cpp
index 4300a81..eebd23b 100644
--- a/procedures/phal/set_SPI_mux.cpp
+++ b/procedures/phal/set_SPI_mux.cpp
@@ -38,7 +38,7 @@
 
     for (const auto& t : targets)
     {
-        writeReg(t, P10_ROOT_CTRL8, 0xFFFFFFFF);
+        writeRegWithMask(t, P10_ROOT_CTRL8, 0xF0000000, 0xF0000000);
     }
 }