diff --git a/ChangeLog b/ChangeLog
index 11d4c39..2ba8d7f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2020-09-07  NIIBE Yutaka  <gniibe@fsij.org>
 
+	* src/openpgp.c (gpg_get_firmware_update_key): Use an array.
+
 	* src/modp256r1.c (modp256r1_add, modp256r1_sub)
 	(modp256r1_reduce): Use memmove.
 
diff --git a/src/openpgp.c b/src/openpgp.c
index 59c57cb..089b66b 100644
--- a/src/openpgp.c
+++ b/src/openpgp.c
@@ -746,10 +746,10 @@ cmd_pgp_gakp (struct eventflag *ccid_comm)
 const uint8_t *
 gpg_get_firmware_update_key (uint8_t keyno)
 {
-  extern uint8_t _updatekey_store;
+  extern uint8_t _updatekey_store[1024];
   const uint8_t *p;
 
-  p = &_updatekey_store + keyno * FIRMWARE_UPDATE_KEY_CONTENT_LEN;
+  p = _updatekey_store + keyno * FIRMWARE_UPDATE_KEY_CONTENT_LEN;
   return p;
 }
 #endif