diff --git a/firmware/target/arm/s5l8700/system-s5l8700.c b/firmware/target/arm/s5l8700/system-s5l8700.c
index e35da90617..72b0caf6db 100644
--- a/firmware/target/arm/s5l8700/system-s5l8700.c
+++ b/firmware/target/arm/s5l8700/system-s5l8700.c
@@ -22,6 +22,7 @@
 #include "kernel.h"
 #include "system.h"
 #include "panic.h"
+#include "system-target.h"
 #ifdef IPOD_NANO2G
 #include "storage.h"
 #include "pmu-target.h"
@@ -208,7 +209,7 @@ void set_cpu_frequency(long frequency)
         /* Vcore = 1.000V */
         pmu_write(0x1e, 0xf);
         /* Allow for voltage to stabilize */
-        sleep(HZ / 100);
+        udelay(100);
         /* FCLK_CPU = PLL0, HCLK = PLL0 / 2 */
         CLKCON = (CLKCON & ~0xFF00FF00) | 0x20003100;
         /* PCLK = HCLK / 2 */
diff --git a/firmware/target/arm/s5l8700/system-target.h b/firmware/target/arm/s5l8700/system-target.h
index 774b53ac23..adc0eb6bfe 100644
--- a/firmware/target/arm/s5l8700/system-target.h
+++ b/firmware/target/arm/s5l8700/system-target.h
@@ -38,4 +38,10 @@
 #define inw(a) (*(volatile unsigned short *) (a))
 #define outw(a,b) (*(volatile unsigned short *) (b) = (a))
 
+static inline void udelay(unsigned usecs)
+{
+    unsigned stop = USEC_TIMER + usecs;
+    while (TIME_BEFORE(USEC_TIMER, stop));
+}
+
 #endif /* SYSTEM_TARGET_H */