diff --git a/firmware/usbdrv/usbdrv.c b/firmware/usbdrv/usbdrv.c
index 21ed554..349748c 100644
--- a/firmware/usbdrv/usbdrv.c
+++ b/firmware/usbdrv/usbdrv.c
@@ -67,7 +67,7 @@ optimizing hints:
 #if USB_CFG_DESCR_PROPS_STRING_0 == 0
 #undef USB_CFG_DESCR_PROPS_STRING_0
 #define USB_CFG_DESCR_PROPS_STRING_0    sizeof(usbDescriptorString0)
-PROGMEM char usbDescriptorString0[] = { /* language descriptor */
+PROGMEM const char usbDescriptorString0[] = { /* language descriptor */
     4,          /* sizeof(usbDescriptorString0): length of descriptor in bytes */
     3,          /* descriptor type */
     0x09, 0x04, /* language index (0x0409 = US-English) */
@@ -77,7 +77,7 @@ PROGMEM char usbDescriptorString0[] = { /* language descriptor */
 #if USB_CFG_DESCR_PROPS_STRING_VENDOR == 0 && USB_CFG_VENDOR_NAME_LEN
 #undef USB_CFG_DESCR_PROPS_STRING_VENDOR
 #define USB_CFG_DESCR_PROPS_STRING_VENDOR   sizeof(usbDescriptorStringVendor)
-PROGMEM int  usbDescriptorStringVendor[] = {
+PROGMEM const  int  usbDescriptorStringVendor[] = {
     USB_STRING_DESCRIPTOR_HEADER(USB_CFG_VENDOR_NAME_LEN),
     USB_CFG_VENDOR_NAME
 };
@@ -86,7 +86,7 @@ PROGMEM int  usbDescriptorStringVendor[] = {
 #if USB_CFG_DESCR_PROPS_STRING_PRODUCT == 0 && USB_CFG_DEVICE_NAME_LEN
 #undef USB_CFG_DESCR_PROPS_STRING_PRODUCT
 #define USB_CFG_DESCR_PROPS_STRING_PRODUCT   sizeof(usbDescriptorStringDevice)
-PROGMEM int  usbDescriptorStringDevice[] = {
+PROGMEM const  int  usbDescriptorStringDevice[] = {
     USB_STRING_DESCRIPTOR_HEADER(USB_CFG_DEVICE_NAME_LEN),
     USB_CFG_DEVICE_NAME
 };
@@ -95,7 +95,7 @@ PROGMEM int  usbDescriptorStringDevice[] = {
 #if USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER == 0 && USB_CFG_SERIAL_NUMBER_LEN
 #undef USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER
 #define USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER    sizeof(usbDescriptorStringSerialNumber)
-PROGMEM int usbDescriptorStringSerialNumber[] = {
+PROGMEM const  int usbDescriptorStringSerialNumber[] = {
     USB_STRING_DESCRIPTOR_HEADER(USB_CFG_SERIAL_NUMBER_LEN),
     USB_CFG_SERIAL_NUMBER
 };
@@ -108,7 +108,7 @@ PROGMEM int usbDescriptorStringSerialNumber[] = {
 #if USB_CFG_DESCR_PROPS_DEVICE == 0
 #undef USB_CFG_DESCR_PROPS_DEVICE
 #define USB_CFG_DESCR_PROPS_DEVICE  sizeof(usbDescriptorDevice)
-PROGMEM char usbDescriptorDevice[] = {    /* USB device descriptor */
+PROGMEM const char usbDescriptorDevice[] = {    /* USB device descriptor */
     18,         /* sizeof(usbDescriptorDevice): length of descriptor in bytes */
     USBDESCR_DEVICE,        /* descriptor type */
     0x10, 0x01,             /* USB version supported */
@@ -139,7 +139,7 @@ PROGMEM char usbDescriptorDevice[] = {    /* USB device descriptor */
 #if USB_CFG_DESCR_PROPS_CONFIGURATION == 0
 #undef USB_CFG_DESCR_PROPS_CONFIGURATION
 #define USB_CFG_DESCR_PROPS_CONFIGURATION   sizeof(usbDescriptorConfiguration)
-PROGMEM char usbDescriptorConfiguration[] = {    /* USB configuration descriptor */
+PROGMEM const char usbDescriptorConfiguration[] = {    /* USB configuration descriptor */
     9,          /* sizeof(usbDescriptorConfiguration): length of descriptor in bytes */
     USBDESCR_CONFIG,    /* descriptor type */
     18 + 7 * USB_CFG_HAVE_INTRIN_ENDPOINT + 7 * USB_CFG_HAVE_INTRIN_ENDPOINT3 +
diff --git a/firmware/usbdrv/usbdrv.h b/firmware/usbdrv/usbdrv.h
index 3a78f30..42fe163 100644
--- a/firmware/usbdrv/usbdrv.h
+++ b/firmware/usbdrv/usbdrv.h
@@ -452,43 +452,43 @@ extern
 #if !(USB_CFG_DESCR_PROPS_DEVICE & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-char usbDescriptorDevice[];
+const char usbDescriptorDevice[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_CONFIGURATION & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-char usbDescriptorConfiguration[];
+const char usbDescriptorConfiguration[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_HID_REPORT & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-char usbDescriptorHidReport[];
+const char usbDescriptorHidReport[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_STRING_0 & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-char usbDescriptorString0[];
+const char usbDescriptorString0[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_STRING_VENDOR & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-int usbDescriptorStringVendor[];
+const int usbDescriptorStringVendor[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_STRING_PRODUCT & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-int usbDescriptorStringDevice[];
+const int usbDescriptorStringDevice[];
 
 extern
 #if !(USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER & USB_PROP_IS_RAM)
 PROGMEM
 #endif
-int usbDescriptorStringSerialNumber[];
+const int usbDescriptorStringSerialNumber[];
 
 #endif /* __ASSEMBLER__ */