diff --git a/Firmware/tmc2130.cpp b/Firmware/tmc2130.cpp
index ae967d330..9afd9e9f8 100644
--- a/Firmware/tmc2130.cpp
+++ b/Firmware/tmc2130.cpp
@@ -131,8 +131,8 @@ void tmc2130_wr_THIGH(uint8_t axis, uint32_t val32);
 #define tmc2130_rd(axis, addr, rval) tmc2130_rx(axis, addr, rval)
 #define tmc2130_wr(axis, addr, wval) tmc2130_tx(axis, (addr) | 0x80, wval)
 
-uint8_t tmc2130_tx(uint8_t axis, uint8_t addr, uint32_t wval);
-uint8_t tmc2130_rx(uint8_t axis, uint8_t addr, uint32_t* rval);
+static void tmc2130_tx(uint8_t axis, uint8_t addr, uint32_t wval);
+static uint8_t tmc2130_rx(uint8_t axis, uint8_t addr, uint32_t* rval);
 
 
 void tmc2130_setup_chopper(uint8_t axis, uint8_t mres, uint8_t current_h, uint8_t current_r);
@@ -627,7 +627,7 @@ inline void tmc2130_cs_high(uint8_t axis)
 #define TMC2130_SPI_TXRX       spi_txrx
 #define TMC2130_SPI_LEAVE()
 
-uint8_t tmc2130_tx(uint8_t axis, uint8_t addr, uint32_t wval)
+static void tmc2130_tx(uint8_t axis, uint8_t addr, uint32_t wval)
 {
 	//datagram1 - request
 	TMC2130_SPI_ENTER();
@@ -641,7 +641,7 @@ uint8_t tmc2130_tx(uint8_t axis, uint8_t addr, uint32_t wval)
 	TMC2130_SPI_LEAVE();
 }
 
-uint8_t tmc2130_rx(uint8_t axis, uint8_t addr, uint32_t* rval)
+static uint8_t tmc2130_rx(uint8_t axis, uint8_t addr, uint32_t* rval)
 {
 	//datagram1 - request
 	TMC2130_SPI_ENTER();