diff --git a/src/main/drivers/bus_spi.c b/src/main/drivers/bus_spi.c
index 732e44941..abec322e8 100644
--- a/src/main/drivers/bus_spi.c
+++ b/src/main/drivers/bus_spi.c
@@ -242,13 +242,12 @@ bool spiTransfer(SPI_TypeDef *instance, uint8_t *out, const uint8_t *in, int len
 void spiSetDivisor(SPI_TypeDef *instance, uint16_t divisor)
 {
 #define BR_CLEAR_MASK 0xFFC7
-
     uint16_t tempRegister;
 
     SPI_Cmd(instance, DISABLE);
 
     tempRegister = (instance->CR1 & BR_CLEAR_MASK);
-    instance->CR1 = (tempRegister | ((ffs(divisor) - 1) << 3));
+    instance->CR1 = (tempRegister | ((ffs(divisor | 0x100) - 2) << 3));
 
     SPI_Cmd(instance, ENABLE);
 }
diff --git a/src/main/drivers/bus_spi_hal.c b/src/main/drivers/bus_spi_hal.c
index 2b6acbaf7..470da18d4 100644
--- a/src/main/drivers/bus_spi_hal.c
+++ b/src/main/drivers/bus_spi_hal.c
@@ -265,10 +265,12 @@ void spiSetDivisor(SPI_TypeDef *instance, uint16_t divisor)
     }
 
     spiDevice[device].hspi.Init.BaudRatePrescaler = (uint8_t []) {
+        0, 0,
         SPI_BAUDRATEPRESCALER_2, SPI_BAUDRATEPRESCALER_4,
         SPI_BAUDRATEPRESCALER_8, SPI_BAUDRATEPRESCALER_16,
         SPI_BAUDRATEPRESCALER_32, SPI_BAUDRATEPRESCALER_64,
-        SPI_BAUDRATEPRESCALER_128, SPI_BAUDRATEPRESCALER_256}[ffs(divisor) - 1];
+        SPI_BAUDRATEPRESCALER_128, SPI_BAUDRATEPRESCALER_256
+    }[ffs(divisor | 0x100)];
 
     if (HAL_SPI_Init(&spiDevice[device].hspi) == HAL_OK)
     {