diff --git a/FATFS/shimatta_sdio_driver/shimatta_sdio-driver.c b/FATFS/shimatta_sdio_driver/shimatta_sdio-driver.c
index 6107854..9b147e0 100644
--- a/FATFS/shimatta_sdio_driver/shimatta_sdio-driver.c
+++ b/FATFS/shimatta_sdio_driver/shimatta_sdio-driver.c
@@ -214,12 +214,11 @@ void initModuleHw(){
 }
 
 void switchPrescaler(uint8_t clkdiv) {
-    SDIO->POWER = 0;
-    __DSB();
-    SDIO->CLKCR &= ~SDIO_CLKCR_CLKDIV; // Clear prescaler
-    SDIO->CLKCR |= (SDIO_CLKCR_CLKDIV & clkdiv); // Set bits
-    __DSB();
-    SDIO->POWER = SDIO_POWER_PWRCTRL_0 | SDIO_POWER_PWRCTRL_1;
+    uint32_t reg;
+    reg = SDIO->CLKCR;
+    reg &= ~SDIO_CLKCR_CLKDIV; // Clear prescaler
+    reg |= (SDIO_CLKCR_CLKDIV & clkdiv); // Set bits
+    SDIO->CLKCR = reg;
 }