diff --git a/cores/esp32/esp32-hal-spi.c b/cores/esp32/esp32-hal-spi.c
index 9dfe34cb8e0..cf302cac88f 100644
--- a/cores/esp32/esp32-hal-spi.c
+++ b/cores/esp32/esp32-hal-spi.c
@@ -532,17 +532,7 @@ uint8_t spiTransferByte(spi_t * spi, uint8_t data)
     return data;
 }
 
-uint32_t __spiTranslate24(uint32_t data)
-{
-    union {
-        uint32_t l;
-        uint8_t b[4];
-    } out;
-    out.l = data;
-    return out.b[2] | (out.b[1] << 8) | (out.b[0] << 16);
-}
-
-uint32_t __spiTranslate32(uint32_t data)
+static uint32_t __spiTranslate32(uint32_t data)
 {
     union {
         uint32_t l;
@@ -630,7 +620,7 @@ uint32_t spiTransferLong(spi_t * spi, uint32_t data)
     return data;
 }
 
-void __spiTransferBytes(spi_t * spi, uint8_t * data, uint8_t * out, uint32_t bytes)
+static void __spiTransferBytes(spi_t * spi, const uint8_t * data, uint8_t * out, uint32_t bytes)
 {
     if(!spi) {
         return;