diff --git a/src/main/drivers/bus_spi_ll.c b/src/main/drivers/bus_spi_ll.c
index 99c4db8191..573a29c61c 100644
--- a/src/main/drivers/bus_spi_ll.c
+++ b/src/main/drivers/bus_spi_ll.c
@@ -27,6 +27,7 @@
 #if defined(USE_SPI)
 
 #include "common/utils.h"
+#include "common/maths.h"
 
 #include "drivers/bus.h"
 #include "drivers/bus_spi.h"
@@ -226,8 +227,10 @@ void spiSetDivisor(SPI_TypeDef *instance, uint16_t divisor)
     }
 #endif
 
+    divisor = constrain(divisor, 2, 256);
+
     LL_SPI_Disable(instance);
-    LL_SPI_SetBaudRatePrescaler(instance, divisor ? (ffs(divisor | 0x100) - 2) << SPI_CR1_BR_Pos : 0);
+    LL_SPI_SetBaudRatePrescaler(instance, (ffs(divisor) - 2) << SPI_CR1_BR_Pos);
     LL_SPI_Enable(instance);
 }
 #endif
diff --git a/src/main/drivers/bus_spi_stdperiph.c b/src/main/drivers/bus_spi_stdperiph.c
index f2626a8543..de7911ea51 100644
--- a/src/main/drivers/bus_spi_stdperiph.c
+++ b/src/main/drivers/bus_spi_stdperiph.c
@@ -26,6 +26,7 @@
 
 #ifdef USE_SPI
 
+#include "common/maths.h"
 #include "drivers/bus.h"
 #include "drivers/bus_spi.h"
 #include "drivers/bus_spi_impl.h"
@@ -186,10 +187,12 @@ void spiSetDivisor(SPI_TypeDef *instance, uint16_t divisor)
     }
 #endif
 
+    divisor = constrain(divisor, 2, 256);
+
     SPI_Cmd(instance, DISABLE);
 
     const uint16_t tempRegister = (instance->CR1 & ~BR_BITS);
-    instance->CR1 = tempRegister | (divisor ? ((ffs(divisor | 0x100) - 2) << 3) : 0);
+    instance->CR1 = tempRegister | ((ffs(divisor) - 2) << 3);
 
     SPI_Cmd(instance, ENABLE);