diff --git a/inc/setup.h b/inc/setup.h
index 8ac47493..5924245e 100644
--- a/inc/setup.h
+++ b/inc/setup.h
@@ -18,7 +18,7 @@
 void setup(void);
 void setup_res(void);
 
-volatile uint32_t ADC_DMA_Buffer0[ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)];
-volatile uint32_t ADC_DMA_Buffer1[ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)];
+extern volatile uint32_t ADC_DMA_Buffer0[ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)];
+extern volatile uint32_t ADC_DMA_Buffer1[ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)];
 
 RCC_ClocksTypeDef RCC_Clocks;
diff --git a/lib/STM32_USB_Device_Library-1.2.0/Class/cdc/src/usbd_cdc_core.c b/lib/STM32_USB_Device_Library-1.2.0/Class/cdc/src/usbd_cdc_core.c
index d6732fe9..6d968250 100644
--- a/lib/STM32_USB_Device_Library-1.2.0/Class/cdc/src/usbd_cdc_core.c
+++ b/lib/STM32_USB_Device_Library-1.2.0/Class/cdc/src/usbd_cdc_core.c
@@ -174,7 +174,7 @@ __ALIGN_BEGIN uint8_t USB_Rx_Buffer   [CDC_DATA_MAX_PACKET_SIZE] __ALIGN_END ;
     #pragma data_alignment=4   
   #endif
 #endif /* USB_OTG_HS_INTERNAL_DMA_ENABLED */
-__ALIGN_BEGIN uint8_t APP_Rx_Buffer   [APP_RX_DATA_SIZE] __ALIGN_END ; 
+__ALIGN_BEGIN uint8_t APP_Rx_Buffer   [APP_RX_DATA_SIZE] __ALIGN_END __attribute__((section(".ram"))); 
 
 
 #ifdef USB_OTG_HS_INTERNAL_DMA_ENABLED
diff --git a/src/comps/hv.c b/src/comps/hv.c
index 9b3d54dd..bf0119c7 100644
--- a/src/comps/hv.c
+++ b/src/comps/hv.c
@@ -57,9 +57,10 @@ HAL_PIN(crc_error);
 HAL_PIN(timeout);
 HAL_PIN(scale);
 
+static volatile packet_to_hv_t packet_to_hv __attribute__((section(".ram")));
+static volatile packet_from_hv_t packet_from_hv __attribute__((section(".ram")));
+
 struct hv_ctx_t {
-  volatile packet_to_hv_t packet_to_hv;
-  volatile packet_from_hv_t packet_from_hv;
   f3_config_data_t config;
   f3_state_data_t state;
   uint16_t addr;
@@ -110,7 +111,7 @@ static void nrt_init(volatile void *ctx_ptr, volatile hal_pin_inst_t *pin_ptr) {
   // DMA2-Config
   DMA_InitStructure.DMA_Channel            = UART_DRV_TX_DMA_CHAN;
   DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) & (UART_DRV->DR);
-  DMA_InitStructure.DMA_Memory0BaseAddr    = (uint32_t) & (ctx->packet_to_hv);
+  DMA_InitStructure.DMA_Memory0BaseAddr    = (uint32_t) & (packet_to_hv);
   DMA_InitStructure.DMA_DIR                = DMA_DIR_MemoryToPeripheral;
   DMA_InitStructure.DMA_BufferSize         = sizeof(packet_to_hv_t);
   DMA_InitStructure.DMA_PeripheralInc      = DMA_PeripheralInc_Disable;
@@ -137,7 +138,7 @@ static void nrt_init(volatile void *ctx_ptr, volatile hal_pin_inst_t *pin_ptr) {
   // DMA2-Config
   DMA_InitStructure.DMA_Channel            = UART_DRV_RX_DMA_CHAN;
   DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t) & (UART_DRV->DR);
-  DMA_InitStructure.DMA_Memory0BaseAddr    = (uint32_t) & (ctx->packet_from_hv);
+  DMA_InitStructure.DMA_Memory0BaseAddr    = (uint32_t) & (packet_from_hv);
   DMA_InitStructure.DMA_DIR                = DMA_DIR_PeripheralToMemory;
   DMA_InitStructure.DMA_BufferSize         = sizeof(packet_from_hv_t);
   DMA_InitStructure.DMA_PeripheralInc      = DMA_PeripheralInc_Disable;
@@ -184,18 +185,18 @@ static void rt_func(float period, volatile void *ctx_ptr, volatile hal_pin_inst_
   uint32_t dma_pos = DMA_GetCurrDataCounter(UART_DRV_RX_DMA);
   if(dma_pos == 0) {
     CRC_ResetDR();
-    uint32_t crc = CRC_CalcBlockCRC((uint32_t *)&(ctx->packet_from_hv), sizeof(packet_from_hv_t) / 4 - 1);
+    uint32_t crc = CRC_CalcBlockCRC((uint32_t *)&(packet_from_hv), sizeof(packet_from_hv_t) / 4 - 1);
 
-    if(crc == ctx->packet_from_hv.crc) {
-      PIN(d_fb)     = ctx->packet_from_hv.d_fb;
-      PIN(q_fb)     = ctx->packet_from_hv.q_fb;
-      PIN(dc_volt)  = ctx->packet_from_hv.dc_volt;
-      PIN(pwm_volt) = ctx->packet_from_hv.pwm_volt;
+    if(crc == packet_from_hv.crc) {
+      PIN(d_fb)     = packet_from_hv.d_fb;
+      PIN(q_fb)     = packet_from_hv.q_fb;
+      PIN(dc_volt)  = packet_from_hv.dc_volt;
+      PIN(pwm_volt) = packet_from_hv.pwm_volt;
       PIN(abs_cur)  = sqrtf(PIN(d_fb) * PIN(d_fb) + PIN(q_fb) * PIN(q_fb));
 
-      uint16_t a         = ctx->packet_from_hv.addr;
+      uint16_t a         = packet_from_hv.addr;
       a                  = CLAMP(a, 0, sizeof(f3_state_data_t) / 4);
-      ctx->state.data[a] = ctx->packet_from_hv.value;
+      ctx->state.data[a] = packet_from_hv.value;
 
       PIN(u_fb)      = ctx->state.pins.u_fb;
       PIN(v_fb)      = ctx->state.pins.v_fb;
@@ -232,24 +233,24 @@ static void rt_func(float period, volatile void *ctx_ptr, volatile hal_pin_inst_
   }
 
   if(e > 0.0) {
-    ctx->packet_to_hv.d_cmd        = d_cmd;
-    ctx->packet_to_hv.q_cmd        = q_cmd;
-    ctx->packet_to_hv.flags.enable = 1;
+    packet_to_hv.d_cmd        = d_cmd;
+    packet_to_hv.q_cmd        = q_cmd;
+    packet_to_hv.flags.enable = 1;
   } else {
-    ctx->packet_to_hv.d_cmd        = 0.0;
-    ctx->packet_to_hv.q_cmd        = 0.0;
-    ctx->packet_to_hv.flags.enable = 0;
+    packet_to_hv.d_cmd        = 0.0;
+    packet_to_hv.q_cmd        = 0.0;
+    packet_to_hv.flags.enable = 0;
   }
-  ctx->packet_to_hv.flags.cmd_type   = PIN(cmd_mode);
-  ctx->packet_to_hv.flags.phase_type = PIN(phase_mode);
-  ctx->packet_to_hv.pos              = pos;
-  ctx->packet_to_hv.vel              = vel;
-  ctx->packet_to_hv.addr             = ctx->addr;
-  ctx->packet_to_hv.value            = ctx->config.data[ctx->addr++];
+  packet_to_hv.flags.cmd_type   = PIN(cmd_mode);
+  packet_to_hv.flags.phase_type = PIN(phase_mode);
+  packet_to_hv.pos              = pos;
+  packet_to_hv.vel              = vel;
+  packet_to_hv.addr             = ctx->addr;
+  packet_to_hv.value            = ctx->config.data[ctx->addr++];
   ctx->addr %= sizeof(f3_config_data_t) / 4;
 
   CRC_ResetDR();
-  ctx->packet_to_hv.crc = CRC_CalcBlockCRC((uint32_t *)&(ctx->packet_to_hv), sizeof(packet_to_hv_t) / 4 - 1);
+  packet_to_hv.crc = CRC_CalcBlockCRC((uint32_t *)&(packet_to_hv), sizeof(packet_to_hv_t) / 4 - 1);
 
   PIN(uart_sr) = UART_DRV->SR;
   PIN(uart_dr) = UART_DRV->DR;
diff --git a/src/comps/sserial.c b/src/comps/sserial.c
index c279e208..8d062be5 100644
--- a/src/comps/sserial.c
+++ b/src/comps/sserial.c
@@ -65,8 +65,9 @@ struct sserial_ctx_t {
   uint32_t foo;
 };
 
-volatile uint8_t rxbuf[128];
-volatile uint8_t txbuf[128];
+static volatile uint8_t rxbuf[128] __attribute__((section(".ram")));
+static volatile uint8_t txbuf[128] __attribute__((section(".ram")));
+
 uint16_t address;  //current address pointer
 int rxpos;
 discovery_rpc_t discovery;
diff --git a/src/main.c b/src/main.c
index 37d0c5be..6efba4ee 100644
--- a/src/main.c
+++ b/src/main.c
@@ -79,7 +79,7 @@ void nv_reset(char *ptr) {
 COMMAND("reset", nv_reset, "reset STMBL");
 
 
-char config[15 * 1024];
+char config[15 * 1024] __attribute__((section(".ram")));
 const char *config_ro = (char *)0x08008000;
 
 
diff --git a/src/setup.c b/src/setup.c
index 4b43464d..5628c7cb 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -9,6 +9,9 @@
 #include "setup.h"
 #include "usbd_cdc_if.h"
 
+volatile uint32_t ADC_DMA_Buffer0 [ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)] __attribute__((section(".ram")));
+volatile uint32_t ADC_DMA_Buffer1 [ADC_TR_COUNT * PID_WAVES * (ADC_OVER_FB0 + ADC_OVER_FB1)] __attribute__((section(".ram")));
+
 void setup() {
   //Enable clocks
   //TODO: small f4 does not have GPIOE
diff --git a/stm32_flash.ld b/stm32_flash.ld
index 1ce0dfdb..883f8119 100644
--- a/stm32_flash.ld
+++ b/stm32_flash.ld
@@ -33,7 +33,7 @@
 ENTRY(Reset_Handler)
 
 /* Highest address of the user mode stack */
-_estack = 0x20020000;    /* end of 128K RAM on AHB bus*/
+_estack = ORIGIN(CCM) + LENGTH(CCM);    /* end of 64K CMM RAM*/
 
 /* Generate a link error if heap and stack don't fit into RAM */
 _Min_Heap_Size = 0;      /* required amount of heap  */
@@ -130,10 +130,10 @@ SECTIONS
   } >FLASH
 
   /* used by the startup to initialize data */
-  _sidata = .;
+  _sidata = LOADADDR(.data);
 
   /* Initialized data sections goes into RAM, load LMA copy after code */
-  .data : AT ( _sidata )
+  .data : 
   {
     . = ALIGN(4);
     _sdata = .;        /* create a global symbol at data start */
@@ -142,8 +142,28 @@ SECTIONS
 
     . = ALIGN(4);
     _edata = .;        /* define a global symbol at data end */
-  } >RAM
+  } >CCM AT> FLASH
 
+  _siccmram = LOADADDR(.ram);
+
+  /* CCM-RAM section 
+  * 
+  * IMPORTANT NOTE! 
+  * If initialized variables will be placed in this section, 
+  * the startup code needs to be modified to copy the init-values.  
+  */
+  .ram :
+  {
+    . = ALIGN(4);
+    _sram = .;       /* create a global symbol at ccmram start */
+    *(.ram)
+    *(.ram*)
+    
+    . = ALIGN(4);
+    _eram = .;       /* create a global symbol at ccmram end */
+  } >RAM AT> FLASH
+
+  
   /* Uninitialized data section */
   . = ALIGN(4);
   .bss :
@@ -158,7 +178,7 @@ SECTIONS
     . = ALIGN(4);
     _ebss = .;         /* define a global symbol at bss end */
     __bss_end__ = _ebss;
-  } >RAM
+  } >CCM
 
   /* User_heap_stack section, used to check that there is enough RAM left */
   ._user_heap_stack :
@@ -169,7 +189,7 @@ SECTIONS
     . = . + _Min_Heap_Size;
     . = . + _Min_Stack_Size;
     . = ALIGN(4);
-  } >RAM
+  } >CCM
 
   /* MEMORY_bank1 section, code must be located here explicitly            */
   /* Example: extern int foo(void) __attribute__ ((section (".mb1text"))); */