diff --git a/libubb/mmcclk.c b/libubb/mmcclk.c
index 77c955e..856ed24 100644
--- a/libubb/mmcclk.c
+++ b/libubb/mmcclk.c
@@ -70,15 +70,16 @@ void mmcclk_start(struct mmcclk *dsc)
 	MSCCDR = dsc->clkdiv;	/* set controller clock */
 	CLKGR &= ~(1 << 7);	/* enable MSC clock */
 
-	MSC_STRPCL = 1 << 3;    /* reset the MSC */
-	while (MSC_STAT & (1 << 15));	/* wait until reset finishes */
+	MSC_STRPCL = MSC_STRPCRL_RESET;	/* reset the MSC */
+	while (MSC_STAT & MSC_STAT_IS_RESETTING);
+					/* wait until reset finishes */
 
 	MSC_CLKRT = dsc->clkrt;	/* set bus clock */
-	MSC_STRPCL = 2;		/* start MMC bus clock output */
+	MSC_STRPCL = MSC_STRPCRL_START_CLOCK;
 }
 
 
 void mmcclk_stop(void)
 {
-	MSC_STRPCL = 1;		/* stop MMC bus clock output */
+	MSC_STRPCL = MSC_STRPCRL_STOP_CLOCK;
 }