diff --git a/firmware/export/config/sansaclipplus.h b/firmware/export/config/sansaclipplus.h
index ab4408a..12151a7 100644
--- a/firmware/export/config/sansaclipplus.h
+++ b/firmware/export/config/sansaclipplus.h
@@ -188,7 +188,7 @@
 #define CONFIG_LED LED_VIRTUAL
 
 /* Define this if you have adjustable CPU frequency */
-//#define HAVE_ADJUSTABLE_CPU_FREQ
+#define HAVE_ADJUSTABLE_CPU_FREQ
 
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
diff --git a/firmware/export/config/sansaclipv2.h b/firmware/export/config/sansaclipv2.h
index 262ed36..4b83b32 100644
--- a/firmware/export/config/sansaclipv2.h
+++ b/firmware/export/config/sansaclipv2.h
@@ -181,7 +181,7 @@
 #define CONFIG_LED LED_VIRTUAL
 
 /* Define this if you have adjustable CPU frequency */
-//#define HAVE_ADJUSTABLE_CPU_FREQ
+#define HAVE_ADJUSTABLE_CPU_FREQ
 
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
diff --git a/firmware/export/config/sansafuzev2.h b/firmware/export/config/sansafuzev2.h
index a21eb34..bc22215 100644
--- a/firmware/export/config/sansafuzev2.h
+++ b/firmware/export/config/sansafuzev2.h
@@ -196,7 +196,7 @@
 #endif /* !BOOTLOADER */
 
 /* Define this if you have adjustable CPU frequency */
-//#define HAVE_ADJUSTABLE_CPU_FREQ
+#define HAVE_ADJUSTABLE_CPU_FREQ
 
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
diff --git a/firmware/target/arm/as3525/system-as3525.c b/firmware/target/arm/as3525/system-as3525.c
index 44e210a..35c60bc 100644
--- a/firmware/target/arm/as3525/system-as3525.c
+++ b/firmware/target/arm/as3525/system-as3525.c
@@ -464,6 +464,7 @@ void set_cpu_frequency(long frequency)
 void set_cpu_frequency(long frequency)
 {
     int oldstatus = disable_irq_save();
+    int cgu_proc, cgu_peri;
 
     /* We only have 2 settings */
     cpu_frequency = (frequency == CPUFREQ_MAX) ? frequency : CPUFREQ_NORMAL;
@@ -471,22 +472,28 @@ void set_cpu_frequency(long frequency)
     if(frequency == CPUFREQ_MAX)
     {
         /* Change PCLK while FCLK is low, so it doesn't go too high */
-        CGU_PERI = (CGU_PERI & ~(0xF << 2)) | (AS3525_PCLK_DIV0 << 2);
+        cgu_peri = (CGU_PERI & ~(0xF << 2)) | (AS3525_PCLK_DIV0 << 2);
 
-        CGU_PROC = ((AS3525_FCLK_POSTDIV << 4) |
+        cgu_proc = ((AS3525_FCLK_POSTDIV << 4) |
                     (AS3525_FCLK_PREDIV  << 2) |
                     AS3525_FCLK_SEL);
     }
     else
     {
-        CGU_PROC = ((AS3525_FCLK_POSTDIV_UNBOOSTED << 4) |
+        cgu_proc = ((AS3525_FCLK_POSTDIV_UNBOOSTED << 4) |
                     (AS3525_FCLK_PREDIV  << 2) |
                     AS3525_FCLK_SEL);
 
         /* Change PCLK after FCLK is low, so it doesn't go too high */
-        CGU_PERI = (CGU_PERI & ~(0xF << 2)) | (AS3525_PCLK_DIV0_UNBOOSTED << 2);
+        cgu_peri = (CGU_PERI & ~(0xF << 2)) | (AS3525_PCLK_DIV0_UNBOOSTED << 2);
     }
 
+    asm(
+        "stmia %[reg], {%[proc], %[peri]}  \n"
+        : /* no output */
+        : [proc]"r"(cgu_proc), [peri]"r"(cgu_peri), [reg]"r"(&CGU_PROC)
+    );
+
     restore_irq(oldstatus);
 }
 #endif