diff --git a/pkg/flashdb/mtd/fal_mtd_port.c b/pkg/flashdb/mtd/fal_mtd_port.c
index 14e23ae825..248cf01859 100644
--- a/pkg/flashdb/mtd/fal_mtd_port.c
+++ b/pkg/flashdb/mtd/fal_mtd_port.c
@@ -74,6 +74,8 @@ struct fal_flash_dev mtd_flash0 = {
 
 void fdb_mtd_init(mtd_dev_t *mtd)
 {
+    assert(mtd);
+
     unsigned sector_size;
     if (_mtd) {
         return;
diff --git a/tests/pkg/flashdb_fal_cfg/main.c b/tests/pkg/flashdb_fal_cfg/main.c
index 1d7e2b3336..2f8eb2f46c 100644
--- a/tests/pkg/flashdb_fal_cfg/main.c
+++ b/tests/pkg/flashdb_fal_cfg/main.c
@@ -103,6 +103,11 @@ static fdb_time_t _get_time(void)
 
 int main(void)
 {
+    if (FDB_MTD == NULL) {
+        puts("No MTD device configured for test, abort.");
+        return -1;
+    }
+
     int init_failed;
     fdb_mtd_init(FDB_MTD);
     size_t size = FDB_MTD->pages_per_sector * FDB_MTD->page_size;