diff --git a/firmware/target/arm/as3525/kernel-as3525.c b/firmware/target/arm/as3525/kernel-as3525.c
index 0f907f61e3..d8f0e23d30 100644
--- a/firmware/target/arm/as3525/kernel-as3525.c
+++ b/firmware/target/arm/as3525/kernel-as3525.c
@@ -24,19 +24,27 @@
 #include "panic.h"
 #include "timer-target.h"
 
+#ifdef HAVE_SCROLLWHEEL
+/* let the timer interrupt twice as often for the scrollwheel polling */
+#define KERNEL_TIMER_FREQ (TIMER_FREQ/2)
+#else
+#define KERNEL_TIMER_FREQ TIMER_FREQ
+#endif
+
 #ifdef HAVE_SCROLLWHEEL
 #include "button-target.h"
 /* The scrollwheel is polled every 5 ms (the tick tasks only every 10) */
-static volatile int poll_scrollwheel = 0;
+static int poll_scrollwheel = 0;
 
 void INT_TIMER2(void)
 {
     if (!poll_scrollwheel)
-        call_tick_tasks();  /* Run through the list of tick tasks */
+        call_tick_tasks();      /* Run through the list of tick tasks
+                                 * (that includes reading the scrollwheel) */
     else
     {
         if (!button_hold())
-            button_read_dbop();
+            button_read_dbop(); /* Read the scrollwheel */
     }
 
     poll_scrollwheel ^= 1;
@@ -55,7 +63,7 @@ void tick_start(unsigned int interval_in_ms)
 {
     int phi = 0;                            /* prescaler bits */
     int prescale = 1;
-    int cycles = TIMER_FREQ / 1000 * interval_in_ms;
+    int cycles = KERNEL_TIMER_FREQ / 1000 * interval_in_ms;
 
     while(cycles > 0x10000)
     {
diff --git a/firmware/target/arm/as3525/timer-target.h b/firmware/target/arm/as3525/timer-target.h
index b5cdb74e85..21ee6e7804 100644
--- a/firmware/target/arm/as3525/timer-target.h
+++ b/firmware/target/arm/as3525/timer-target.h
@@ -25,14 +25,7 @@ bool __timer_set(long cycles, bool set);
 bool __timer_register(void);
 void __timer_unregister(void);
 
-#ifdef HAVE_SCROLLWHEEL
-/* The scrollwheel is polled every 5 ms (the tick tasks still every 10ms) */
-#define TIMER_DIV (16*2)
-#else
-#define TIMER_DIV (16)
-#endif
-
-#define TIMER_FREQ (24000000 / TIMER_DIV)
+#define TIMER_FREQ (24000000 / 16)
 
 #define __TIMER_SET(cycles, set) \
     __timer_set(cycles, set)