diff --git a/firmware/export/config/sansaclipplus.h b/firmware/export/config/sansaclipplus.h
index 6b84faabd4..faa22259a6 100644
--- a/firmware/export/config/sansaclipplus.h
+++ b/firmware/export/config/sansaclipplus.h
@@ -198,6 +198,9 @@
 /* Define this if you have adjustable CPU frequency */
 #define HAVE_ADJUSTABLE_CPU_FREQ
 
+/*define this to enable CPU voltage scaling on AMS devices*/
+#define HAVE_ADJUSTABLE_CPU_VOLTAGE
+
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
 #define BOOTDIR "/.rockbox"
diff --git a/firmware/export/config/sansaclipv2.h b/firmware/export/config/sansaclipv2.h
index 5f6d195810..301cfc8c7f 100644
--- a/firmware/export/config/sansaclipv2.h
+++ b/firmware/export/config/sansaclipv2.h
@@ -194,6 +194,9 @@
 /* Define this if you have adjustable CPU frequency */
 #define HAVE_ADJUSTABLE_CPU_FREQ
 
+/*define this to enable CPU voltage scaling on AMS devices*/
+#define HAVE_ADJUSTABLE_CPU_VOLTAGE
+
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
 #define BOOTDIR "/.rockbox"
diff --git a/firmware/export/config/sansaclipzip.h b/firmware/export/config/sansaclipzip.h
index b028dadb75..ea1c57193d 100644
--- a/firmware/export/config/sansaclipzip.h
+++ b/firmware/export/config/sansaclipzip.h
@@ -197,6 +197,9 @@
 /* Define this if you have adjustable CPU frequency */
 #define HAVE_ADJUSTABLE_CPU_FREQ
 
+/*define this to enable CPU voltage scaling on AMS devices*/
+#define HAVE_ADJUSTABLE_CPU_VOLTAGE
+
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
 #define BOOTDIR "/.rockbox"
diff --git a/firmware/export/config/sansafuzev2.h b/firmware/export/config/sansafuzev2.h
index 3b4fb2279b..523a331df1 100644
--- a/firmware/export/config/sansafuzev2.h
+++ b/firmware/export/config/sansafuzev2.h
@@ -210,6 +210,9 @@
 /* Define this if you have adjustable CPU frequency */
 #define HAVE_ADJUSTABLE_CPU_FREQ
 
+/*define this to enable CPU voltage scaling on AMS devices*/
+#define HAVE_ADJUSTABLE_CPU_VOLTAGE
+
 #define BOOTFILE_EXT    "sansa"
 #define BOOTFILE        "rockbox." BOOTFILE_EXT
 #define BOOTDIR "/.rockbox"
diff --git a/firmware/target/arm/as3525/system-as3525.c b/firmware/target/arm/as3525/system-as3525.c
index 22aa90aad6..edd80f4fb2 100644
--- a/firmware/target/arm/as3525/system-as3525.c
+++ b/firmware/target/arm/as3525/system-as3525.c
@@ -460,7 +460,7 @@ void set_cpu_frequency(long frequency)
 {
     if(frequency == CPUFREQ_MAX)
     {
-#if 0
+#ifdef HAVE_ADJUSTABLE_CPU_VOLTAGE
         /* Set CVDD1 power supply */
         ascodec_write_pmu(0x17, 1, 0x80 | 47);
         /* dely for voltage rising */
@@ -481,7 +481,7 @@ void set_cpu_frequency(long frequency)
         cpu_frequency = CPUFREQ_NORMAL;
 
         /* Set CVDD1 power supply */
-#if 0
+#ifdef HAVE_ADJUSTABLE_CPU_VOLTAGE
 #ifdef SANSA_CLIPZIP
         ascodec_write_pmu(0x17, 1, 0x80 | 19);
 #else