diff --git a/src/apdu.h b/src/apdu.h
index 8c1475d..9e15aef 100644
--- a/src/apdu.h
+++ b/src/apdu.h
@@ -44,7 +44,7 @@ typedef struct cmd {
 } cmd_t;
 
 extern uint8_t num_apps;
-extern app_t apps[8];
+extern app_t apps[16];
 extern app_t *current_app;
 
 PACK(struct apdu {
diff --git a/src/main.c b/src/main.c
index 855bbcf..e59b5e3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -49,7 +49,7 @@ extern void do_flash();
 extern void low_flash_init();
 extern void init_otp_files();
 
-app_t apps[8];
+app_t apps[16];
 uint8_t num_apps = 0;
 
 app_t *current_app = NULL;
@@ -57,11 +57,8 @@ app_t *current_app = NULL;
 const uint8_t *ccid_atr = NULL;
 
 bool app_exists(const uint8_t *aid, size_t aid_len) {
-    if (current_app && current_app->aid && (current_app->aid + 1 == aid || !memcmp(current_app->aid + 1, aid, aid_len))) {
-        return true;
-    }
     for (int a = 0; a < num_apps; a++) {
-        if (!memcmp(apps[a].aid + 1, aid, MIN(aid_len, apps[a].aid[0]))) {
+        if (apps[a].aid[0] == aid_len && !memcmp(apps[a].aid + 1, aid, MIN(aid_len, apps[a].aid[0]))) {
             return true;
         }
     }
@@ -82,12 +79,12 @@ int register_app(int (*select_aid)(app_t *, uint8_t), const uint8_t *aid) {
 }
 
 int select_app(const uint8_t *aid, size_t aid_len) {
-    if (current_app && current_app->aid && (current_app->aid + 1 == aid || !memcmp(current_app->aid + 1, aid, MIN(current_app->aid[0], aid_len)))) {
+    if (current_app && current_app->aid && current_app->aid[0] == aid_len && (current_app->aid + 1 == aid || !memcmp(current_app->aid + 1, aid, MIN(current_app->aid[0], aid_len)))) {
         current_app->select_aid(current_app, 0);
         return PICOKEY_OK;
     }
     for (int a = 0; a < num_apps; a++) {
-        if (!memcmp(apps[a].aid + 1, aid, MIN(aid_len, apps[a].aid[0]))) {
+        if (apps[a].aid[0] == aid_len && !memcmp(apps[a].aid + 1, aid, MIN(aid_len, apps[a].aid[0]))) {
             if (current_app) {
                 if (current_app->aid && !memcmp(current_app->aid + 1, aid, MIN(current_app->aid[0], aid_len))) {
                     current_app->select_aid(current_app, 1);