diff --git a/src/hsm/cmd_key_unwrap.c b/src/hsm/cmd_key_unwrap.c
index 13b7160..d214bf9 100644
--- a/src/hsm/cmd_key_unwrap.c
+++ b/src/hsm/cmd_key_unwrap.c
@@ -30,8 +30,8 @@ int cmd_key_unwrap() {
         return SW_SECURITY_STATUS_NOT_SATISFIED();
     }
     int key_type = dkek_type_key(apdu.data);
-    uint8_t kdom = -1, *allowed = NULL, prkd_buf[128];
-    size_t allowed_len = 0, prkd_len = 0;
+    uint8_t kdom = -1, *allowed = NULL;
+    size_t allowed_len = 0;
     if (key_type == 0x0) {
         return SW_DATA_INVALID();
     }
@@ -50,12 +50,10 @@ int cmd_key_unwrap() {
             mbedtls_rsa_free(&ctx);
             return SW_EXEC_ERROR();
         }
-        int key_size = ctx.len;
         mbedtls_rsa_free(&ctx);
         if (r != CCID_OK) {
             return SW_EXEC_ERROR();
         }
-        prkd_len = asn1_build_prkd_rsa(NULL, 0, NULL, 0, key_size * 8, prkd_buf, sizeof(prkd_buf));
     }
     else if (key_type & PICO_KEYS_KEY_EC) {
         mbedtls_ecdsa_context ctx;
@@ -72,12 +70,10 @@ int cmd_key_unwrap() {
             mbedtls_ecdsa_free(&ctx);
             return SW_EXEC_ERROR();
         }
-        int key_size = ctx.grp.nbits;
         mbedtls_ecdsa_free(&ctx);
         if (r != CCID_OK) {
             return SW_EXEC_ERROR();
         }
-        prkd_len = asn1_build_prkd_ecc(NULL, 0, NULL, 0, key_size, prkd_buf, sizeof(prkd_buf));
     }
     else if (key_type & PICO_KEYS_KEY_AES) {
         uint8_t aes_key[64];
@@ -113,7 +109,6 @@ int cmd_key_unwrap() {
         if (r != CCID_OK) {
             return SW_EXEC_ERROR();
         }
-        prkd_len = asn1_build_prkd_aes(NULL, 0, NULL, 0, key_size * 8, prkd_buf, sizeof(prkd_buf));
     }
     if ((allowed != NULL && allowed_len > 0) || kdom >= 0) {
         size_t meta_len = (allowed_len > 0 ? 2 + allowed_len : 0) + (kdom >= 0 ? 3 : 0);
@@ -134,13 +129,6 @@ int cmd_key_unwrap() {
             return r;
         }
     }
-    if (prkd_len > 0) {
-        file_t *fpk = file_new((PRKD_PREFIX << 8) | key_id);
-        r = flash_write_data_to_file(fpk, prkd_buf, prkd_len);
-        if (r != 0) {
-            return SW_EXEC_ERROR();
-        }
-    }
     if (res_APDU_size > 0) {
         file_t *fpk = file_new((EE_CERTIFICATE_PREFIX << 8) | key_id);
         r = flash_write_data_to_file(fpk, res_APDU, res_APDU_size);