diff --git a/STM32F1/boards.txt b/STM32F1/boards.txt
index d9c5df5..24202fc 100644
--- a/STM32F1/boards.txt
+++ b/STM32F1/boards.txt
@@ -38,6 +38,14 @@ mapleMini.menu.bootloader_version.bootloader20.upload.flash.maximum_size=122880
 mapleMini.menu.bootloader_version.bootloader20.upload.maximum_size=122880
 mapleMini.menu.bootloader_version.bootloader20.upload.altID=2
 
+#-- CPU Clock frequency
+mapleMini.menu.cpu_speed.speed_72mhz=72Mhz (Normal)
+mapleMini.menu.cpu_speed.speed_72mhz.build.f_cpu=72000000L
+
+mapleMini.menu.cpu_speed.speed_48mhz=48Mhz (Slow - with USB)
+mapleMini.menu.cpu_speed.speed_48mhz.build.f_cpu=48000000L
+
+
 ##############################################################
 maple.name=Maple (Rev 3)
 
@@ -217,6 +225,13 @@ genericSTM32F103C.menu.upload_method.jlinkMethod.upload.protocol=jlink
 genericSTM32F103C.menu.upload_method.jlinkMethod.upload.tool=jlink_upload
 genericSTM32F103C.menu.upload_method.jlinkMethod.build.upload_flags=-DCONFIG_MAPLE_MINI_NO_DISABLE_DEBUG=1 -DSERIAL_USB -DGENERIC_BOOTLOADER 
 
+#-- CPU Clock frequency
+genericSTM32F103C.menu.cpu_speed.speed_72mhz=72Mhz (Normal)
+genericSTM32F103C.menu.cpu_speed.speed_72mhz.build.f_cpu=72000000L
+
+genericSTM32F103C.menu.cpu_speed.speed_48mhz=48Mhz (Slow - with USB)
+genericSTM32F103C.menu.cpu_speed.speed_48mhz.build.f_cpu=48000000L
+
 ########################### Generic STM32F103R ###########################
 
 genericSTM32F103R.name=Generic STM32F103R series
diff --git a/STM32F1/variants/STM32VLD/wirish/boards_setup.cpp b/STM32F1/variants/STM32VLD/wirish/boards_setup.cpp
index 9de4d53..f6a28c0 100644
--- a/STM32F1/variants/STM32VLD/wirish/boards_setup.cpp
+++ b/STM32F1/variants/STM32VLD/wirish/boards_setup.cpp
@@ -71,7 +71,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/generic_gd32f103c/wirish/boards_setup.cpp b/STM32F1/variants/generic_gd32f103c/wirish/boards_setup.cpp
index a5a26be..3df1fe7 100644
--- a/STM32F1/variants/generic_gd32f103c/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_gd32f103c/wirish/boards_setup.cpp
@@ -80,7 +80,7 @@ namespace wirish {
 			#elif F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/generic_stm32f103c/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103c/wirish/boards_setup.cpp
index 1f833af..5516282 100644
--- a/STM32F1/variants/generic_stm32f103c/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103c/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif			
         }
 
diff --git a/STM32F1/variants/generic_stm32f103r/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103r/wirish/boards_setup.cpp
index 25060bb..d7774f7 100644
--- a/STM32F1/variants/generic_stm32f103r/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103r/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/generic_stm32f103r8/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103r8/wirish/boards_setup.cpp
index 9c04e74..7c93977 100644
--- a/STM32F1/variants/generic_stm32f103r8/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103r8/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/generic_stm32f103t/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103t/wirish/boards_setup.cpp
index 1f833af..5516282 100644
--- a/STM32F1/variants/generic_stm32f103t/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103t/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif			
         }
 
diff --git a/STM32F1/variants/generic_stm32f103v/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103v/wirish/boards_setup.cpp
index 2f638f4..1f23679 100644
--- a/STM32F1/variants/generic_stm32f103v/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103v/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/generic_stm32f103z/wirish/boards_setup.cpp b/STM32F1/variants/generic_stm32f103z/wirish/boards_setup.cpp
index 78868b2..e2cfe4a 100644
--- a/STM32F1/variants/generic_stm32f103z/wirish/boards_setup.cpp
+++ b/STM32F1/variants/generic_stm32f103z/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/hytiny_stm32f103t/wirish/boards_setup.cpp b/STM32F1/variants/hytiny_stm32f103t/wirish/boards_setup.cpp
index 5d762c7..df39347 100644
--- a/STM32F1/variants/hytiny_stm32f103t/wirish/boards_setup.cpp
+++ b/STM32F1/variants/hytiny_stm32f103t/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif				
         }
 
diff --git a/STM32F1/variants/maple/wirish/boards_setup.cpp b/STM32F1/variants/maple/wirish/boards_setup.cpp
index d7b8ef8..1071d6d 100644
--- a/STM32F1/variants/maple/wirish/boards_setup.cpp
+++ b/STM32F1/variants/maple/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/maple_mini/wirish/boards_setup.cpp b/STM32F1/variants/maple_mini/wirish/boards_setup.cpp
index 5d762c7..df39347 100644
--- a/STM32F1/variants/maple_mini/wirish/boards_setup.cpp
+++ b/STM32F1/variants/maple_mini/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif				
         }
 
diff --git a/STM32F1/variants/maple_ret6/wirish/boards_setup.cpp b/STM32F1/variants/maple_ret6/wirish/boards_setup.cpp
index d7b8ef8..1071d6d 100644
--- a/STM32F1/variants/maple_ret6/wirish/boards_setup.cpp
+++ b/STM32F1/variants/maple_ret6/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }
 
diff --git a/STM32F1/variants/microduino/wirish/boards_setup.cpp b/STM32F1/variants/microduino/wirish/boards_setup.cpp
index 6a26b91..e899843 100644
--- a/STM32F1/variants/microduino/wirish/boards_setup.cpp
+++ b/STM32F1/variants/microduino/wirish/boards_setup.cpp
@@ -48,7 +48,11 @@
 // works for F103 performance line MCUs, which is all that LeafLabs
 // currently officially supports).
 #ifndef BOARD_RCC_PLLMUL
-#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #if F_CPU==72000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_9
+  #elif F_CPU==48000000
+	#define BOARD_RCC_PLLMUL RCC_PLLMUL_6
+  #endif
 #endif
 
 namespace wirish {
@@ -71,7 +75,7 @@ namespace wirish {
 			#if F_CPU == 72000000
 			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);
 			#elif F_CPU == 48000000
-			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1_5);			
+			rcc_set_prescaler(RCC_PRESCALER_USB, RCC_USB_SYSCLK_DIV_1);			
 			#endif	
         }