diff --git a/platform/samd11/usb.c b/platform/samd11/usb.c
index cf10500..881ace6 100644
--- a/platform/samd11/usb.c
+++ b/platform/samd11/usb.c
@@ -28,6 +28,7 @@
 
 /*- Includes ----------------------------------------------------------------*/
 #include <stdbool.h>
+#include <stdalign.h>
 #include <string.h>
 #include "udc.h"
 #include "usb.h"
@@ -115,18 +116,21 @@ void usb_handle_standard_request(usb_request_t *request)
         {
           const char *str = usb_strings[index];
           int len = strlen(str);
+          int size = len*2 + 2;
+          alignas(4) uint8_t buf[size];
 
-          memset(usb_string_descriptor_buffer, 0, sizeof(usb_string_descriptor_buffer));
-
-          usb_string_descriptor_buffer[0] = len*2 + 2;
-          usb_string_descriptor_buffer[1] = USB_STRING_DESCRIPTOR;
+          buf[0] = size;
+          buf[1] = USB_STRING_DESCRIPTOR;
 
           for (int i = 0; i < len; i++)
-            usb_string_descriptor_buffer[2 + i*2] = str[i];
+          {
+            buf[2 + i*2] = str[i];
+            buf[3 + i*2] = 0;
+          }
 
-          length = LIMIT(length, usb_string_descriptor_buffer[0]);
+          length = LIMIT(length, size);
 
-          udc_control_send(usb_string_descriptor_buffer, length);
+          udc_control_send(buf, length);
         }
         else
         {
@@ -134,8 +138,10 @@ void usb_handle_standard_request(usb_request_t *request)
         }
       }
       else
+      {
         udc_control_stall();
-    }  break;
+      }
+    } break;
 
     case USB_CMD(OUT, DEVICE, STANDARD, SET_ADDRESS):
     {
diff --git a/platform/samd11/usb_descriptors.c b/platform/samd11/usb_descriptors.c
index 6126b36..b5936f4 100644
--- a/platform/samd11/usb_descriptors.c
+++ b/platform/samd11/usb_descriptors.c
@@ -148,5 +148,3 @@ const char *const usb_strings[] =
   [USB_STR_INTERFACE]     = "Main Interface",
 };
 
-alignas(4) uint8_t usb_string_descriptor_buffer[64];
-
diff --git a/platform/samd11/usb_descriptors.h b/platform/samd11/usb_descriptors.h
index 2ab8b4b..b2fbb43 100644
--- a/platform/samd11/usb_descriptors.h
+++ b/platform/samd11/usb_descriptors.h
@@ -79,7 +79,6 @@ extern const usb_configuration_hierarchy_t usb_configuration_hierarchy;
 extern const uint8_t usb_hid_report_descriptor[33];
 extern const usb_string_descriptor_zero_t usb_string_descriptor_zero;
 extern const char *const usb_strings[];
-extern uint8_t usb_string_descriptor_buffer[64];
 
 #endif // _USB_DESCRIPTORS_H_
 
diff --git a/platform/samd21/main.c b/platform/samd21/main.c
index 603654d..33d41d1 100644
--- a/platform/samd21/main.c
+++ b/platform/samd21/main.c
@@ -30,6 +30,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include <stdalign.h>
 #include <string.h>
 #include "samd21.h"
 #include "hal_gpio.h"
@@ -43,8 +44,8 @@
 #define APP_EP_RECV    2
 
 /*- Variables ---------------------------------------------------------------*/
-ALIGNED(4) uint8_t app_request_buffer[DAP_CONFIG_PACKET_SIZE];
-ALIGNED(4) uint8_t app_response_buffer[DAP_CONFIG_PACKET_SIZE];
+alignas(4) uint8_t app_request_buffer[DAP_CONFIG_PACKET_SIZE];
+alignas(4) uint8_t app_response_buffer[DAP_CONFIG_PACKET_SIZE];
 
 /*- Implementations ---------------------------------------------------------*/
 
diff --git a/platform/samd21/usb.c b/platform/samd21/usb.c
index cf10500..e428256 100644
--- a/platform/samd21/usb.c
+++ b/platform/samd21/usb.c
@@ -28,6 +28,7 @@
 
 /*- Includes ----------------------------------------------------------------*/
 #include <stdbool.h>
+#include <stdalign.h>
 #include <string.h>
 #include "udc.h"
 #include "usb.h"
@@ -115,18 +116,21 @@ void usb_handle_standard_request(usb_request_t *request)
         {
           const char *str = usb_strings[index];
           int len = strlen(str);
+          int size = len*2 + 2;
+          alignas(4) uint8_t buf[size];
 
-          memset(usb_string_descriptor_buffer, 0, sizeof(usb_string_descriptor_buffer));
-
-          usb_string_descriptor_buffer[0] = len*2 + 2;
-          usb_string_descriptor_buffer[1] = USB_STRING_DESCRIPTOR;
+          buf[0] = size;
+          buf[1] = USB_STRING_DESCRIPTOR;
 
           for (int i = 0; i < len; i++)
-            usb_string_descriptor_buffer[2 + i*2] = str[i];
+          {
+            buf[2 + i*2] = str[i];
+            buf[3 + i*2] = 0;
+          }
 
-          length = LIMIT(length, usb_string_descriptor_buffer[0]);
+          length = LIMIT(length, size);
 
-          udc_control_send(usb_string_descriptor_buffer, length);
+          udc_control_send(buf, length);
         }
         else
         {
diff --git a/platform/samd21/usb_descriptors.c b/platform/samd21/usb_descriptors.c
index 6736db5..b5e140b 100644
--- a/platform/samd21/usb_descriptors.c
+++ b/platform/samd21/usb_descriptors.c
@@ -28,11 +28,12 @@
 
 
 /*- Includes ----------------------------------------------------------------*/
+#include <stdalign.h>
 #include "usb.h"
 #include "usb_descriptors.h"
 
 /*- Variables ---------------------------------------------------------------*/
-ALIGNED(4) const usb_device_descriptor_t usb_device_descriptor =
+const alignas(4) usb_device_descriptor_t usb_device_descriptor =
 {
   .bLength            = sizeof(usb_device_descriptor_t),
   .bDescriptorType    = USB_DEVICE_DESCRIPTOR,
@@ -50,7 +51,7 @@ ALIGNED(4) const usb_device_descriptor_t usb_device_descriptor =
   .bNumConfigurations = 1,
 };
 
-ALIGNED(4) const usb_configuration_hierarchy_t usb_configuration_hierarchy =
+const alignas(4) usb_configuration_hierarchy_t usb_configuration_hierarchy =
 {
   .configuration =
   {
@@ -109,7 +110,7 @@ ALIGNED(4) const usb_configuration_hierarchy_t usb_configuration_hierarchy =
   },
 };
 
-ALIGNED(4) const uint8_t usb_hid_report_descriptor[33] =
+const alignas(4) uint8_t usb_hid_report_descriptor[33] =
 {
   0x06, 0x00, 0xff,  // Usage Page (Vendor Defined 0xFF00)
   0x09, 0x01,        // Usage (0x01)
@@ -129,7 +130,7 @@ ALIGNED(4) const uint8_t usb_hid_report_descriptor[33] =
   0xc0,              // End Collection
 };
 
-ALIGNED(4) const usb_string_descriptor_zero_t usb_string_descriptor_zero =
+const alignas(4) usb_string_descriptor_zero_t usb_string_descriptor_zero =
 {
   .bLength               = sizeof(usb_string_descriptor_zero_t),
   .bDescriptorType       = USB_STRING_DESCRIPTOR,
@@ -145,5 +146,3 @@ const char *const usb_strings[] =
   [USB_STR_INTERFACE]     = "Main Interface",
 };
 
-ALIGNED(4) uint8_t usb_string_descriptor_buffer[64];
-
diff --git a/platform/samd21/usb_descriptors.h b/platform/samd21/usb_descriptors.h
index 2ab8b4b..b2fbb43 100644
--- a/platform/samd21/usb_descriptors.h
+++ b/platform/samd21/usb_descriptors.h
@@ -79,7 +79,6 @@ extern const usb_configuration_hierarchy_t usb_configuration_hierarchy;
 extern const uint8_t usb_hid_report_descriptor[33];
 extern const usb_string_descriptor_zero_t usb_string_descriptor_zero;
 extern const char *const usb_strings[];
-extern uint8_t usb_string_descriptor_buffer[64];
 
 #endif // _USB_DESCRIPTORS_H_
 
diff --git a/platform/samd21/utils.h b/platform/samd21/utils.h
index 60b8372..db6861a 100644
--- a/platform/samd21/utils.h
+++ b/platform/samd21/utils.h
@@ -30,8 +30,6 @@
 #define _UTILS_H_
 
 /*- Definitions -------------------------------------------------------------*/
-#define ALIGNED(a)      __attribute__((__aligned__(a)))
-
 #define PACK            __attribute__((packed))
 
 #define INLINE          static inline __attribute__((always_inline))