diff --git a/features/storage/kvstore/conf/tdb_internal/mbed_lib.json b/features/storage/kvstore/conf/tdb_internal/mbed_lib.json
index 140f7e5e26..8b1403703e 100644
--- a/features/storage/kvstore/conf/tdb_internal/mbed_lib.json
+++ b/features/storage/kvstore/conf/tdb_internal/mbed_lib.json
@@ -15,6 +15,10 @@
             "internal_size": "0x8000",
             "internal_base_address": "0x00028000"
         },
+        "LPC55S69_NS": {
+            "internal_size": "0x8000",
+            "internal_base_address": "0x00090000"
+        },
         "DISCO_H747I": {
             "internal_size": "2*FLASH_SECTOR_SIZE",
             "internal_base_address": "0x080C0000"
diff --git a/features/storage/kvstore/tdbstore/TDBStore.cpp b/features/storage/kvstore/tdbstore/TDBStore.cpp
index d7166c722e..6595964121 100644
--- a/features/storage/kvstore/tdbstore/TDBStore.cpp
+++ b/features/storage/kvstore/tdbstore/TDBStore.cpp
@@ -134,6 +134,11 @@ TDBStore::TDBStore(BlockDevice *bd) : _ram_table(0), _max_keys(0),
     for (int i = 0; i < _max_open_iterators; i++) {
         _iterator_table[i] = { 0 };
     }
+
+    /* Minimum space required by Reserved area and master record */
+    MBED_ASSERT(bd->size()
+                >= (align_up(RESERVED_AREA_SIZE + sizeof(reserved_trailer_t), _prog_size)
+                    + record_size(master_rec_key, sizeof(master_record_data_t))));
 }
 
 TDBStore::~TDBStore()