diff --git a/armsrc/i2c.c b/armsrc/i2c.c
index ca3cb46fd..016ae2f13 100644
--- a/armsrc/i2c.c
+++ b/armsrc/i2c.c
@@ -407,7 +407,7 @@ bool I2C_WriteByte(uint8_t data, uint8_t device_cmd, uint8_t device_address) {
 
 //Sends array of data (Array, length, command to be written , SlaveDevice address  ).
 // len = uint16 because we need to write up to 256 bytes
-bool I2C_BufferWrite(uint8_t *data, uint16_t len, uint8_t device_cmd, uint8_t device_address) {
+bool I2C_BufferWrite(const uint8_t *data, uint16_t len, uint8_t device_cmd, uint8_t device_address) {
     bool bBreak = true;
     do {
         if (!I2C_Start())
@@ -602,7 +602,7 @@ int16_t I2C_ReadFW(uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t
     return readcount;
 }
 
-bool I2C_WriteFW(uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t device_address) {
+bool I2C_WriteFW(const uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t device_address) {
     //START, 0xB0, 0x00, 0x00, xx, yy, zz, ......, STOP
     bool bBreak = true;
 
@@ -772,7 +772,7 @@ void SmartCardAtr(void) {
 //    StopTicks();
 }
 
-void SmartCardRaw(smart_card_raw_t *p) {
+void SmartCardRaw(const smart_card_raw_t *p) {
     LED_D_ON();
 
     uint16_t len = 0;
diff --git a/armsrc/i2c.h b/armsrc/i2c.h
index 972704c1b..6fa8b8809 100644
--- a/armsrc/i2c.h
+++ b/armsrc/i2c.h
@@ -41,12 +41,12 @@ void I2C_Reset_EnterBootloader(void);
 bool I2C_WriteCmd(uint8_t device_cmd, uint8_t device_address);
 
 bool I2C_WriteByte(uint8_t data, uint8_t device_cmd, uint8_t device_address);
-bool I2C_BufferWrite(uint8_t *data, uint16_t len, uint8_t device_cmd, uint8_t device_address);
+bool I2C_BufferWrite(const uint8_t *data, uint16_t len, uint8_t device_cmd, uint8_t device_address);
 int16_t I2C_BufferRead(uint8_t *data, uint16_t len, uint8_t device_cmd, uint8_t device_address);
 
 // for firmware
 int16_t I2C_ReadFW(uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t device_address);
-bool I2C_WriteFW(uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t device_address);
+bool I2C_WriteFW(const uint8_t *data, uint8_t len, uint8_t msb, uint8_t lsb, uint8_t device_address);
 
 bool sc_rx_bytes(uint8_t *dest, uint16_t *destlen);
 //
@@ -54,7 +54,7 @@ bool GetATR(smart_card_atr_t *card_ptr, bool verbose);
 
 // generice functions
 void SmartCardAtr(void);
-void SmartCardRaw(smart_card_raw_t *p);
+void SmartCardRaw(const smart_card_raw_t *p);
 void SmartCardUpgrade(uint64_t arg0);
 void SmartCardSetBaud(uint64_t arg0);
 void SmartCardSetClock(uint64_t arg0);