diff --git a/firmware/target/arm/s5l8700/kernel-s5l8700.c b/firmware/target/arm/s5l8700/kernel-s5l8700.c
index cfa13aab2c..6f131d93f8 100644
--- a/firmware/target/arm/s5l8700/kernel-s5l8700.c
+++ b/firmware/target/arm/s5l8700/kernel-s5l8700.c
@@ -44,13 +44,13 @@ void tick_start(unsigned int interval_in_ms)
     
     /* configure timer for 10 kHz */
     TBCMD = (1 << 1);   /* TB_CLR */
-    TBPRE = 624;        /* prescaler */
+    TBPRE = 625 - 1;    /* prescaler */
     TBCON = (0 << 13) | /* TB_INT1_EN */
             (1 << 12) | /* TB_INT0_EN */
             (0 << 11) | /* TB_START */
             (2 << 8) |  /* TB_CS = PCLK / 16 */
             (0 << 4);   /* TB_MODE_SEL = interval mode */
-    TBDATA0 = cycles-1; /* set interval period */
+    TBDATA0 = cycles;   /* set interval period */
     TBCMD = (1 << 0);   /* TB_EN */
 
     /* enable timer interrupt */
diff --git a/firmware/target/arm/s5l8700/pcm-s5l8700.c b/firmware/target/arm/s5l8700/pcm-s5l8700.c
index 38b581b80c..7a4bdeb174 100644
--- a/firmware/target/arm/s5l8700/pcm-s5l8700.c
+++ b/firmware/target/arm/s5l8700/pcm-s5l8700.c
@@ -75,7 +75,7 @@ void pcm_play_lock(void)
 void pcm_play_unlock(void)
 {
     if (--locked == 0) {
-        INTMSK |= ~(1 << 10);
+        INTMSK |= (1 << 10);
     }
 }