diff --git a/examples/device/cdc_msc/src/msc_disk.c b/examples/device/cdc_msc/src/msc_disk.c
index 42b080cc..cad2602a 100644
--- a/examples/device/cdc_msc/src/msc_disk.c
+++ b/examples/device/cdc_msc/src/msc_disk.c
@@ -188,6 +188,9 @@ int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void* buff
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
   uint8_t const* addr = msc_disk[lba] + offset;
   memcpy(buffer, addr, bufsize);
 
@@ -211,6 +214,9 @@ int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t*
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
 #ifndef CFG_EXAMPLE_MSC_READONLY
   uint8_t* addr = msc_disk[lba] + offset;
   memcpy(addr, buffer, bufsize);
diff --git a/examples/device/cdc_msc_freertos/src/msc_disk.c b/examples/device/cdc_msc_freertos/src/msc_disk.c
index a4826fbe..b9205f0c 100644
--- a/examples/device/cdc_msc_freertos/src/msc_disk.c
+++ b/examples/device/cdc_msc_freertos/src/msc_disk.c
@@ -178,6 +178,9 @@ int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void* buff
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
   uint8_t const* addr = msc_disk[lba] + offset;
   memcpy(buffer, addr, bufsize);
 
@@ -190,6 +193,9 @@ int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t*
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
 #ifndef CFG_EXAMPLE_MSC_READONLY
   uint8_t* addr = msc_disk[lba] + offset;
   memcpy(addr, buffer, bufsize);
diff --git a/examples/device/dynamic_configuration/src/msc_disk.c b/examples/device/dynamic_configuration/src/msc_disk.c
index a4826fbe..b9205f0c 100644
--- a/examples/device/dynamic_configuration/src/msc_disk.c
+++ b/examples/device/dynamic_configuration/src/msc_disk.c
@@ -178,6 +178,9 @@ int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void* buff
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
   uint8_t const* addr = msc_disk[lba] + offset;
   memcpy(buffer, addr, bufsize);
 
@@ -190,6 +193,9 @@ int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t*
 {
   (void) lun;
 
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
 #ifndef CFG_EXAMPLE_MSC_READONLY
   uint8_t* addr = msc_disk[lba] + offset;
   memcpy(addr, buffer, bufsize);
diff --git a/examples/device/msc_dual_lun/src/msc_disk_dual.c b/examples/device/msc_dual_lun/src/msc_disk_dual.c
index 3cc59b46..18d3ca0d 100644
--- a/examples/device/msc_dual_lun/src/msc_disk_dual.c
+++ b/examples/device/msc_dual_lun/src/msc_disk_dual.c
@@ -268,6 +268,9 @@ bool tud_msc_start_stop_cb(uint8_t lun, uint8_t power_condition, bool start, boo
 // Copy disk's data to buffer (up to bufsize) and return number of copied bytes.
 int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize)
 {
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
   uint8_t const* addr = (lun ? msc_disk1[lba] : msc_disk0[lba]) + offset;
   memcpy(buffer, addr, bufsize);
 
@@ -289,6 +292,9 @@ bool tud_msc_is_writable_cb (uint8_t lun)
 // Process data in buffer to disk's storage and return number of written bytes
 int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t* buffer, uint32_t bufsize)
 {
+  // out of ramdisk
+  if ( lba >= DISK_BLOCK_NUM ) return -1;
+
 #ifndef CFG_EXAMPLE_MSC_READONLY
   uint8_t* addr = (lun ? msc_disk1[lba] : msc_disk0[lba])  + offset;
   memcpy(addr, buffer, bufsize);