diff --git a/src/tpm2_wrap.c b/src/tpm2_wrap.c
index f5ad008..8dfd269 100644
--- a/src/tpm2_wrap.c
+++ b/src/tpm2_wrap.c
@@ -5009,24 +5009,7 @@ int wolfTPM2_CSR_SetCustomExt(WOLFTPM2_DEV* dev, WOLFTPM2_CSR* csr,
     }
 #if defined(WOLFSSL_ASN_TEMPLATE) && defined(WOLFSSL_CUSTOM_OID) && \
     defined(HAVE_OID_ENCODING)
-
-    if (XSTRLEN(oid) >= WOLFTPM2_MAX_OID_STRING_SZ) {
-        return BUFFER_E;
-    }
-
-    XSTRNCPY(csr->exts_oids[csr->customCertExtCount], oid,
-             WOLFTPM2_MAX_OID_STRING_SZ);
-    rc = wc_SetCustomExtension(&csr->req, critical,
-                               csr->exts_oids[csr->customCertExtCount], der,
-                               derSz);
-
-    if (rc == 0) {
-        csr->customCertExtCount++;
-    } else {
-        XMEMSET(csr->exts_oids[csr->customCertExtCount], 0,
-                WOLFTPM2_MAX_OID_STRING_SZ);
-    }
-
+    rc = wc_SetCustomExtension(&csr->req, critical, oid, der, derSz);
 #else
     (void)critical;
     (void)oid;
diff --git a/wolftpm/tpm2_types.h b/wolftpm/tpm2_types.h
old mode 100644
new mode 100755
index e15af34..e6f301b
--- a/wolftpm/tpm2_types.h
+++ b/wolftpm/tpm2_types.h
@@ -89,7 +89,7 @@ typedef int64_t  INT64;
     #include <wolfssl/wolfcrypt/hash.h>
     #include <wolfssl/wolfcrypt/rsa.h>
     #include <wolfssl/wolfcrypt/ecc.h>
-    #include <wolfssl/wolfcrypt/asn.h>
+    #include <wolfssl/wolfcrypt/asn_public.h>
     #include <wolfssl/wolfcrypt/hmac.h>
     #include <wolfssl/wolfcrypt/aes.h>
     #ifdef WOLF_CRYPTO_CB
diff --git a/wolftpm/tpm2_wrap.h b/wolftpm/tpm2_wrap.h
old mode 100644
new mode 100755
index 4a542fe..991d5d5
--- a/wolftpm/tpm2_wrap.h
+++ b/wolftpm/tpm2_wrap.h
@@ -83,24 +83,10 @@ typedef struct WOLFTPM2_HMAC {
 } WOLFTPM2_HMAC;
 
 #ifdef WOLFTPM2_CERT_GEN
-
-#ifndef WOLFTPM2_NUM_CUSTOM_EXT
-#define WOLFTPM2_NUM_CUSTOM_EXT NUM_CUSTOM_EXT
-#endif
-
-#ifndef WOLFTPM2_MAX_OID_STRING_SZ
-#define WOLFTPM2_MAX_OID_STRING_SZ MAX_OID_STRING_SZ
-#endif
-
 typedef struct WOLFTPM2_CSR {
-#if defined(WOLFSSL_ASN_TEMPLATE) && defined(WOLFSSL_CUSTOM_OID) && \
-    defined(HAVE_OID_ENCODING)
-    int customCertExtCount;
-    char exts_oids[WOLFTPM2_NUM_CUSTOM_EXT][WOLFTPM2_MAX_OID_STRING_SZ];
-#endif /* WOLFSSL_ASN_TEMPLATE && WOLFSSL_CUSTOM_OID && HAVE_OID_ENCODING */
     Cert req;
 } WOLFTPM2_CSR;
-#endif /* WOLFTPM2_CERT_GEN */
+#endif
 
 #ifndef WOLFTPM2_MAX_BUFFER
     #define WOLFTPM2_MAX_BUFFER 2048
diff --git a/wrapper/CSharp/wolfTPM-tests.cs b/wrapper/CSharp/wolfTPM-tests.cs
index 99b6aaf..05a6544 100644
--- a/wrapper/CSharp/wolfTPM-tests.cs
+++ b/wrapper/CSharp/wolfTPM-tests.cs
@@ -105,7 +105,8 @@ namespace tpm_csharp_test
             Console.WriteLine(sb.ToString());
         }
 
-        private static void DumpByteArray(string filename, byte[] bytes) {
+        private static void DumpByteArray(string filename, byte[] bytes)
+        {
             var writer = new BinaryWriter(File.OpenWrite(filename));
             writer.Write(bytes);
         }
diff --git a/wrapper/CSharp/wolfTPM.cs b/wrapper/CSharp/wolfTPM.cs
index 2d8c977..965ab50 100644
--- a/wrapper/CSharp/wolfTPM.cs
+++ b/wrapper/CSharp/wolfTPM.cs
@@ -747,7 +747,7 @@ namespace wolfTPM
         private static extern int wolfTPM2_CSR_SetCustomExt(IntPtr dev,
                                                             IntPtr csr,
                                                             int critical,
-                                                            string oid,
+                                                            byte[] oid,
                                                             byte[] der,
                                                             uint derSz);
 
@@ -763,9 +763,13 @@ namespace wolfTPM
         /// <returns>Success: 0</returns>
         public int SetCustomExtension(string oid, string der, int critical)
         {
+            /* Allocate a buffer here for OID and DER, since the underlying
+             * library wants to have the pointer available later. The garbage
+             * collection at end of caller frees memory */
+            byte[] oidBuf = Encoding.ASCII.GetBytes(oid);
             byte[] derBuf = Encoding.ASCII.GetBytes(der);
             int rc = wolfTPM2_CSR_SetCustomExt(IntPtr.Zero, csr, critical,
-                                               oid, derBuf, (uint)der.Length);
+                                              oidBuf, derBuf, (uint)der.Length);
             if (rc != (int)Status.TPM_RC_SUCCESS &&
                 rc != (int)Status.NOT_COMPILED_IN) {
                 throw new WolfTpm2Exception(