diff --git a/lib/platform_compat.h b/lib/platform_compat.h
index 2a9664f8..39a8e0c7 100644
--- a/lib/platform_compat.h
+++ b/lib/platform_compat.h
@@ -192,6 +192,15 @@ int get_interface_ipv6_by_index(uint32_t netif_index, int temporary, uint8_t* ad
 uint32_t get_default_route_netif_index(int family);
 
 
+// Cross-platform mkdir
+#ifdef _WIN32
+    #include <direct.h>
+    #define utun_mkdir(path, mode) _mkdir(path)
+#else
+    #include <sys/stat.h>
+    #define utun_mkdir(path, mode) mkdir(path, mode)
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/utun_instance.c b/src/utun_instance.c
index ead3e984..65f14d8e 100644
--- a/src/utun_instance.c
+++ b/src/utun_instance.c
@@ -30,6 +30,7 @@
 #include "../lib/platform_compat.h"
 #include "../lib/mem.h"
 #include "../lib/ll_queue.h"
+#include <openssl/sha.h>
 
 
 
@@ -92,6 +93,11 @@ static int instance_init_common(struct UTUN_INSTANCE* instance, struct UASYNC* u
         DEBUG_ERROR(DEBUG_CATEGORY_CRYPTO, "Failed to derive Ed25519 pubkey");
         return -1;
     }
+    {
+        uint8_t ed_priv_hash[SHA512_DIGEST_LENGTH];
+        SHA512(instance->my_keys.private_key, SC_PRIVKEY_SIZE, ed_priv_hash);
+        memcpy(instance->my_ed25519_privkey, ed_priv_hash, SC_PRIVKEY_SIZE);
+    }
     DEBUG_INFO(DEBUG_CATEGORY_CRYPTO, "Ed25519 pubkey derived successfully");
     
     // Initialize networks queue (indexed by 56-bit network id)
@@ -287,7 +293,7 @@ struct UTUN_INSTANCE* utun_instance_create(struct UASYNC* ua, const char *config
         }
         int remaining = (int)(sizeof(instance->stats_dir) - dir_len - 8);
         if (remaining > 0) snprintf(instance->stats_dir + dir_len, remaining, "/stats");
-        mkdir(instance->stats_dir, 0755);
+        utun_mkdir(instance->stats_dir, 0755);
         DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "Metrics stats dir: %s", instance->stats_dir);
     }
     
diff --git a/tests/test_db_sync.c b/tests/test_db_sync.c
index 607c84e8..61bf2591 100644
--- a/tests/test_db_sync.c
+++ b/tests/test_db_sync.c
@@ -67,10 +67,10 @@ static int create_temp_configs(void) {
 
     // Create LMDB directories (parent first, then child)
     char db_path[320];
-    snprintf(db_path, sizeof(db_path), "%s/db_a", temp_dir); mkdir(db_path, 0755);
-    snprintf(db_path, sizeof(db_path), "%s/db_a/sync", temp_dir); mkdir(db_path, 0755);
-    snprintf(db_path, sizeof(db_path), "%s/db_b", temp_dir); mkdir(db_path, 0755);
-    snprintf(db_path, sizeof(db_path), "%s/db_b/sync", temp_dir); mkdir(db_path, 0755);
+    snprintf(db_path, sizeof(db_path), "%s/db_a", temp_dir); utun_mkdir(db_path, 0755);
+    snprintf(db_path, sizeof(db_path), "%s/db_a/sync", temp_dir); utun_mkdir(db_path, 0755);
+    snprintf(db_path, sizeof(db_path), "%s/db_b", temp_dir); utun_mkdir(db_path, 0755);
+    snprintf(db_path, sizeof(db_path), "%s/db_b/sync", temp_dir); utun_mkdir(db_path, 0755);
 
     if (write_file(config_a,
         "[global]\n"