diff --git a/scd/app-dinsig.c b/scd/app-dinsig.c
index 5a2713e6b..378ec421c 100644
--- a/scd/app-dinsig.c
+++ b/scd/app-dinsig.c
@@ -100,7 +100,7 @@ do_learn_status (app_t app, ctrl_t ctrl, unsigned int flags)
 
   /* Return the certificate of the card holder. */
   fid = 0xC000;
-  len = app_help_read_length_of_cert (app->slot, fid, &certoff);
+  len = app_help_read_length_of_cert (app_get_slot (app), fid, &certoff);
   if (!len)
     return 0; /* Card has not been personalized. */
 
@@ -113,7 +113,8 @@ do_learn_status (app_t app, ctrl_t ctrl, unsigned int flags)
 
   /* Now we need to read the certificate, so that we can get the
      public key out of it.  */
-  err = iso7816_read_binary (app->slot, certoff, len-certoff, &der, &derlen);
+  err = iso7816_read_binary (app_get_slot (app), certoff, len-certoff,
+                             &der, &derlen);
   if (err)
     {
       log_info ("error reading entire certificate from FID 0x%04X: %s\n",
@@ -192,14 +193,14 @@ do_readcert (app_t app, const char *certid,
   /* Read the entire file.  fixme: This could be optimized by first
      reading the header to figure out how long the certificate
      actually is. */
-  err = iso7816_select_file (app->slot, fid, 0);
+  err = iso7816_select_file (app_get_slot (app), fid, 0);
   if (err)
     {
       log_error ("error selecting FID 0x%04X: %s\n", fid, gpg_strerror (err));
       return err;
     }
 
-  err = iso7816_read_binary (app->slot, 0, 0, &buffer, &buflen);
+  err = iso7816_read_binary (app_get_slot (app), 0, 0, &buffer, &buflen);
   if (err)
     {
       log_error ("error reading certificate from FID 0x%04X: %s\n",
@@ -292,7 +293,7 @@ verify_pin (app_t app,
   pininfo.maxlen = 8;
 
   if (!opt.disable_pinpad
-      && !iso7816_check_pinpad (app->slot, ISO7816_VERIFY, &pininfo) )
+      && !iso7816_check_pinpad (app_get_slot (app), ISO7816_VERIFY, &pininfo) )
     {
       rc = pincb (pincb_arg,
                   _("||Please enter your PIN at the reader's pinpad"),
@@ -303,7 +304,7 @@ verify_pin (app_t app,
                     gpg_strerror (rc));
           return rc;
         }
-      rc = iso7816_verify_kp (app->slot, 0x81, &pininfo);
+      rc = iso7816_verify_kp (app_get_slot (app), 0x81, &pininfo);
       /* Dismiss the prompt. */
       pincb (pincb_arg, NULL, NULL);
     }
@@ -344,7 +345,8 @@ verify_pin (app_t app,
           return gpg_error (GPG_ERR_BAD_PIN);
         }
 
-      rc = iso7816_verify (app->slot, 0x81, pinvalue, strlen (pinvalue));
+      rc = iso7816_verify (app_get_slot (app), 0x81,
+                           pinvalue, strlen (pinvalue));
       if (gpg_err_code (rc) == GPG_ERR_INV_VALUE)
         {
           /* We assume that ISO 9564-1 encoding is used and we failed
@@ -365,7 +367,8 @@ verify_pin (app_t app,
             paddedpin[i++] = (((*s - '0') << 4) | 0x0f);
           while (i < sizeof paddedpin)
             paddedpin[i++] = 0xff;
-          rc = iso7816_verify (app->slot, 0x81, paddedpin, sizeof paddedpin);
+          rc = iso7816_verify (app_get_slot (app), 0x81,
+                               paddedpin, sizeof paddedpin);
         }
       xfree (pinvalue);
     }
@@ -483,7 +486,7 @@ do_sign (app_t app, ctrl_t ctrl, const char *keyidstr, int hashalgo,
 
   rc = verify_pin (app, pincb, pincb_arg);
   if (!rc)
-    rc = iso7816_compute_ds (app->slot, 0, data, datalen, 0,
+    rc = iso7816_compute_ds (app_get_slot (app), 0, data, datalen, 0,
                              outdata, outdatalen);
   return rc;
 }
@@ -533,7 +536,7 @@ do_change_pin (app_t app, ctrl_t ctrl,  const char *chvnostr,
       return err;
     }
 
-  err = iso7816_change_reference_data (app->slot, 0x81,
+  err = iso7816_change_reference_data (app_get_slot (app), 0x81,
                                        oldpin, oldpinlen,
                                        pinvalue, strlen (pinvalue));
   xfree (pinvalue);
@@ -548,7 +551,7 @@ gpg_error_t
 app_select_dinsig (app_t app)
 {
   static char const aid[] = { 0xD2, 0x76, 0x00, 0x00, 0x66, 0x01 };
-  int slot = app->slot;
+  int slot = app_get_slot (app);
   int rc;
 
   rc = iso7816_select_application (slot, aid, sizeof aid, 0);
diff --git a/scd/app-nks.c b/scd/app-nks.c
index b09b71e67..c14041506 100644
--- a/scd/app-nks.c
+++ b/scd/app-nks.c
@@ -870,7 +870,7 @@ do_learn_status_core (app_t app, ctrl_t ctrl, unsigned int flags,
         {
           size_t len;
 
-          len = app_help_read_length_of_cert (app->slot,
+          len = app_help_read_length_of_cert (app_get_slot (app),
                                               filelist[i].fid, NULL);
           if (len)
             {
@@ -962,7 +962,7 @@ readcert_from_ef (app_t app, int fid, unsigned char **cert, size_t *certlen)
   /* Read the entire file.  fixme: This could be optimized by first
      reading the header to figure out how long the certificate
      actually is. */
-  err = iso7816_select_file (app->slot, fid, 0);
+  err = iso7816_select_file (app_get_slot (app), fid, 0);
   if (err)
     {
       log_error ("nks: error selecting FID 0x%04X: %s\n",
@@ -970,7 +970,7 @@ readcert_from_ef (app_t app, int fid, unsigned char **cert, size_t *certlen)
       return err;
     }
 
-  err = iso7816_read_binary (app->slot, 0, 0, &buffer, &buflen);
+  err = iso7816_read_binary (app_get_slot (app), 0, 0, &buffer, &buflen);
   if (err)
     {
       log_error ("nks: error reading certificate from FID 0x%04X: %s\n",
@@ -1515,7 +1515,7 @@ do_writekey (app_t app, ctrl_t ctrl,
 /*   mse[10] = 0x82; /\* RSA public exponent of up to 4 bytes.  *\/ */
 /*   mse[12] = rsa_e_len; */
 /*   memcpy (mse+12, rsa_e, rsa_e_len); */
-/*   err = iso7816_manage_security_env (app->slot, 0x81, 0xB6, */
+/*   err = iso7816_manage_security_env (app_get_slot (app), 0x81, 0xB6, */
 /*                                      mse, sizeof mse); */
 
  leave:
@@ -1659,7 +1659,7 @@ verify_pin (app_t app, int pwid, const char *desc,
     }
 
   if (!opt.disable_pinpad
-      && !iso7816_check_pinpad (app->slot, ISO7816_VERIFY, &pininfo) )
+      && !iso7816_check_pinpad (app_get_slot (app), ISO7816_VERIFY, &pininfo) )
     {
       prompt = make_prompt (app, remaining, desc, extrapromptline);
       rc = pincb (pincb_arg, prompt, NULL);
@@ -1671,7 +1671,7 @@ verify_pin (app_t app, int pwid, const char *desc,
           return rc;
         }
 
-      rc = iso7816_verify_kp (app->slot, pwid, &pininfo);
+      rc = iso7816_verify_kp (app_get_slot (app), pwid, &pininfo);
       pincb (pincb_arg, NULL, NULL);  /* Dismiss the prompt. */
     }
   else
@@ -1694,7 +1694,8 @@ verify_pin (app_t app, int pwid, const char *desc,
           return rc;
         }
 
-      rc = iso7816_verify (app->slot, pwid, pinvalue, strlen (pinvalue));
+      rc = iso7816_verify (app_get_slot (app), pwid,
+                           pinvalue, strlen (pinvalue));
       xfree (pinvalue);
     }
 
diff --git a/scd/app-openpgp.c b/scd/app-openpgp.c
index da6dc7a89..e7288ef2d 100644
--- a/scd/app-openpgp.c
+++ b/scd/app-openpgp.c
@@ -384,7 +384,7 @@ get_cached_data (app_t app, int tag,
   else
     exmode = 0;
 
-  err = iso7816_get_data (app->slot, exmode, tag, &p, &len);
+  err = iso7816_get_data (app_get_slot (app), exmode, tag, &p, &len);
   if (err)
     return err;
   if (len)
@@ -515,7 +515,7 @@ get_one_do (app_t app, int tag, unsigned char **result, size_t *nbytes,
   if (app->appversion > 0x0100 && data_objects[i].get_immediate_in_v11)
     {
       exmode = 0;
-      rc = iso7816_get_data (app->slot, exmode, tag, &buffer, &buflen);
+      rc = iso7816_get_data (app_get_slot (app), exmode, tag, &buffer, &buflen);
       if (rc)
         {
           *r_rc = rc;
@@ -857,7 +857,7 @@ store_fpr (app_t app, int keynumber, u32 timestamp, unsigned char *fpr,
   tag2 = 0xCE + keynumber;
   flush_cache_item (app, 0xCD);
 
-  rc = iso7816_put_data (app->slot, 0, tag, fpr, 20);
+  rc = iso7816_put_data (app_get_slot (app), 0, tag, fpr, 20);
   if (rc)
     log_error (_("failed to store the fingerprint: %s\n"),gpg_strerror (rc));
 
@@ -870,7 +870,7 @@ store_fpr (app_t app, int keynumber, u32 timestamp, unsigned char *fpr,
       buf[2] = timestamp >>  8;
       buf[3] = timestamp;
 
-      rc = iso7816_put_data (app->slot, 0, tag2, buf, 4);
+      rc = iso7816_put_data (app_get_slot (app), 0, tag2, buf, 4);
       if (rc)
         log_error (_("failed to store the creation date: %s\n"),
                    gpg_strerror (rc));
@@ -1756,7 +1756,7 @@ get_public_key (app_t app, int keyno)
           le_value = 256; /* Use legacy value. */
         }
 
-      err = iso7816_read_public_key (app->slot, exmode,
+      err = iso7816_read_public_key (app_get_slot (app), exmode,
                                      (keyno == 0? "\xB6" :
                                       keyno == 1? "\xB8" : "\xA4"),
                                      2, le_value, &buffer, &buflen);
@@ -2279,7 +2279,7 @@ verify_a_chv (app_t app,
       /* Special case for def_chv2 mechanism. */
       if (opt.verbose)
         log_info (_("using default PIN as %s\n"), "CHV2");
-      rc = iso7816_verify (app->slot, 0x82, "123456", 6);
+      rc = iso7816_verify (app_get_slot (app), 0x82, "123456", 6);
       if (rc)
         {
           /* Verification of CHV2 with the default PIN failed,
@@ -2312,7 +2312,7 @@ verify_a_chv (app_t app,
   }
 
   if (!opt.disable_pinpad
-      && !iso7816_check_pinpad (app->slot, ISO7816_VERIFY, &pininfo)
+      && !iso7816_check_pinpad (app_get_slot (app), ISO7816_VERIFY, &pininfo)
       && !check_pinpad_request (app, &pininfo, 0))
     {
       /* The reader supports the verify command through the pinpad.
@@ -2328,7 +2328,7 @@ verify_a_chv (app_t app,
                     gpg_strerror (rc));
           return rc;
         }
-      rc = iso7816_verify_kp (app->slot, 0x80+chvno, &pininfo);
+      rc = iso7816_verify_kp (app_get_slot (app), 0x80+chvno, &pininfo);
       /* Dismiss the prompt. */
       pincb (pincb_arg, NULL, NULL);
 
@@ -2359,7 +2359,8 @@ verify_a_chv (app_t app,
 
       rc = pin2hash_if_kdf (app, chvno, *pinvalue, pinlen);
       if (!rc)
-        rc = iso7816_verify (app->slot, 0x80+chvno, *pinvalue, *pinlen);
+        rc = iso7816_verify (app_get_slot (app),
+                             0x80 + chvno, *pinvalue, *pinlen);
     }
 
   if (rc)
@@ -2501,7 +2502,8 @@ verify_chv3 (app_t app,
         return rc;
 
       if (!opt.disable_pinpad
-          && !iso7816_check_pinpad (app->slot, ISO7816_VERIFY, &pininfo)
+          && !iso7816_check_pinpad (app_get_slot (app),
+                                    ISO7816_VERIFY, &pininfo)
           && !check_pinpad_request (app, &pininfo, 1))
         {
           /* The reader supports the verify command through the pinpad. */
@@ -2514,7 +2516,7 @@ verify_chv3 (app_t app,
                         gpg_strerror (rc));
               return rc;
             }
-          rc = iso7816_verify_kp (app->slot, 0x83, &pininfo);
+          rc = iso7816_verify_kp (app_get_slot (app), 0x83, &pininfo);
           /* Dismiss the prompt. */
           pincb (pincb_arg, NULL, NULL);
         }
@@ -2543,7 +2545,7 @@ verify_chv3 (app_t app,
 
           rc = pin2hash_if_kdf (app, 3, pinvalue, &pinlen);
           if (!rc)
-            rc = iso7816_verify (app->slot, 0x83, pinvalue, pinlen);
+            rc = iso7816_verify (app_get_slot (app), 0x83, pinvalue, pinlen);
           xfree (pinvalue);
         }
 
@@ -2638,7 +2640,8 @@ do_setattr (app_t app, ctrl_t ctrl, const char *name,
     exmode = -254; /* Command chaining with max. 254 bytes.  */
   else
     exmode = 0;
-  rc = iso7816_put_data (app->slot, exmode, table[idx].tag, value, valuelen);
+  rc = iso7816_put_data (app_get_slot (app),
+                         exmode, table[idx].tag, value, valuelen);
   if (rc)
     log_error ("failed to set '%s': %s\n", table[idx].name, gpg_strerror (rc));
 
@@ -2787,7 +2790,7 @@ do_change_pin (app_t app, ctrl_t ctrl,  const char *chvnostr,
       /* Version 2 cards.  */
 
       if (!opt.disable_pinpad
-          && !iso7816_check_pinpad (app->slot,
+          && !iso7816_check_pinpad (app_get_slot (app),
                                     ISO7816_CHANGE_REFERENCE_DATA, &pininfo)
           && !check_pinpad_request (app, &pininfo, chvno == 3))
         use_pinpad = 1;
@@ -2930,7 +2933,7 @@ do_change_pin (app_t app, ctrl_t ctrl,  const char *chvnostr,
               rc = pin2hash_if_kdf (app, 1, buffer+pinlen0, &pinlen);
             }
           if (!rc)
-            rc = iso7816_reset_retry_counter_with_rc (app->slot, 0x81,
+            rc = iso7816_reset_retry_counter_with_rc (app_get_slot (app), 0x81,
                                                       buffer, pinlen0+pinlen);
           wipememory (buffer, pinlen0 + pinlen);
           xfree (buffer);
@@ -2947,31 +2950,37 @@ do_change_pin (app_t app, ctrl_t ctrl,  const char *chvnostr,
         {
           rc = pin2hash_if_kdf (app, 0, pinvalue, &pinlen);
           if (!rc)
-            rc = iso7816_put_data (app->slot, 0, 0xD3, pinvalue, pinlen);
+            rc = iso7816_put_data (app_get_slot (app),
+                                   0, 0xD3, pinvalue, pinlen);
         }
     }
   else if (reset_mode)
     {
       rc = pin2hash_if_kdf (app, 1, pinvalue, &pinlen);
       if (!rc)
-        rc = iso7816_reset_retry_counter (app->slot, 0x81, pinvalue, pinlen);
+        rc = iso7816_reset_retry_counter (app_get_slot (app),
+                                          0x81, pinvalue, pinlen);
       if (!rc && !app->app_local->extcap.is_v2)
-        rc = iso7816_reset_retry_counter (app->slot, 0x82, pinvalue, pinlen);
+        rc = iso7816_reset_retry_counter (app_get_slot (app),
+                                          0x82, pinvalue, pinlen);
     }
   else if (!app->app_local->extcap.is_v2)
     {
       /* Version 1 cards.  */
       if (chvno == 1 || chvno == 2)
         {
-          rc = iso7816_change_reference_data (app->slot, 0x81, NULL, 0,
+          rc = iso7816_change_reference_data (app_get_slot (app),
+                                              0x81, NULL, 0,
                                               pinvalue, strlen (pinvalue));
           if (!rc)
-            rc = iso7816_change_reference_data (app->slot, 0x82, NULL, 0,
+            rc = iso7816_change_reference_data (app_get_slot (app),
+                                                0x82, NULL, 0,
                                                 pinvalue, strlen (pinvalue));
         }
       else /* CHVNO == 3 */
         {
-          rc = iso7816_change_reference_data (app->slot, 0x80 + chvno, NULL, 0,
+          rc = iso7816_change_reference_data (app_get_slot (app),
+                                              0x80 + chvno, NULL, 0,
                                               pinvalue, strlen (pinvalue));
         }
     }
@@ -3045,7 +3054,7 @@ does_key_exist (app_t app, int keyidx, int generating, int force)
 
   assert (keyidx >=0 && keyidx <= 2);
 
-  if (iso7816_get_data (app->slot, 0, 0x006E, &buffer, &buflen))
+  if (iso7816_get_data (app_get_slot (app), 0, 0x006E, &buffer, &buflen))
     {
       log_error (_("error reading application data\n"));
       return gpg_error (GPG_ERR_GENERAL);
@@ -3378,7 +3387,7 @@ change_keyattr (app_t app, int keyno, const unsigned char *buf, size_t buflen,
     return err;
 
   /* Change the attribute.  */
-  err = iso7816_put_data (app->slot, 0, 0xC1+keyno, buf, buflen);
+  err = iso7816_put_data (app_get_slot (app), 0, 0xC1+keyno, buf, buflen);
   if (err)
     log_error ("error changing key attribute (key=%d)\n", keyno+1);
   else
@@ -3770,7 +3779,7 @@ rsa_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
         exmode = -254;
       else
         exmode = 0;
-      err = iso7816_put_data_odd (app->slot, exmode, 0x3fff,
+      err = iso7816_put_data_odd (app_get_slot (app), exmode, 0x3fff,
                                   template, template_len);
     }
   else
@@ -3820,7 +3829,7 @@ rsa_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
         goto leave;
 
       /* Store the key. */
-      err = iso7816_put_data (app->slot, 0,
+      err = iso7816_put_data (app_get_slot (app), 0,
                               (app->appversion > 0x0007? 0xE0:0xE9)+keyno,
                               template, template_len);
     }
@@ -4094,7 +4103,7 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
         exmode = -254;
       else
         exmode = 0;
-      err = iso7816_put_data_odd (app->slot, exmode, 0x3fff,
+      err = iso7816_put_data_odd (app_get_slot (app), exmode, 0x3fff,
                                   template, template_len);
       xfree (template);
     }
@@ -4262,7 +4271,7 @@ do_genkey (app_t app, ctrl_t ctrl,  const char *keynostr, const char *keytype,
 
   log_info (_("please wait while key is being generated ...\n"));
   start_at = time (NULL);
-  err = iso7816_generate_keypair (app->slot, exmode, 0x80, 0,
+  err = iso7816_generate_keypair (app_get_slot (app), exmode, 0x80, 0,
                                   (keyno == 0? "\xB6" :
                                    keyno == 1? "\xB8" : "\xA4"),
                                   2, le_value, &buffer, &buflen);
@@ -4623,7 +4632,8 @@ do_sign (app_t app, ctrl_t ctrl, const char *keyidstr, int hashalgo,
       char *pinvalue;
       int pinlen;
 
-      rc = verify_a_chv (app, pincb, pincb_arg, 1, sigcount, &pinvalue, &pinlen);
+      rc = verify_a_chv (app, pincb, pincb_arg, 1, sigcount,
+                         &pinvalue, &pinlen);
       if (rc)
         return rc;
 
@@ -4636,7 +4646,7 @@ do_sign (app_t app, ctrl_t ctrl, const char *keyidstr, int hashalgo,
          pinpad has been used. */
       if (!app->did_chv2 && pinvalue && !app->app_local->extcap.is_v2)
         {
-          rc = iso7816_verify (app->slot, 0x82, pinvalue, pinlen);
+          rc = iso7816_verify (app_get_slot (app), 0x82, pinvalue, pinlen);
           if (gpg_err_code (rc) == GPG_ERR_BAD_PIN)
             rc = gpg_error (GPG_ERR_PIN_NOT_SYNCED);
           if (rc)
@@ -4664,7 +4674,7 @@ do_sign (app_t app, ctrl_t ctrl, const char *keyidstr, int hashalgo,
       exmode = 0;
       le_value = 0;
     }
-  rc = iso7816_compute_ds (app->slot, exmode, data, datalen, le_value,
+  rc = iso7816_compute_ds (app_get_slot (app), exmode, data, datalen, le_value,
                            outdata, outdatalen);
   if (!rc && app->force_chv1)
     app->did_chv1 = 0;
@@ -4756,7 +4766,7 @@ do_auth (app_t app, ctrl_t ctrl, const char *keyidstr,
           exmode = 0;
           le_value = 0;
         }
-      rc = iso7816_internal_authenticate (app->slot, exmode,
+      rc = iso7816_internal_authenticate (app_get_slot (app), exmode,
                                           indata, indatalen, le_value,
                                           outdata, outdatalen);
     }
@@ -4951,7 +4961,7 @@ do_decipher (app_t app, ctrl_t ctrl, const char *keyidstr,
   else
     exmode = le_value = 0;
 
-  rc = iso7816_decipher (app->slot, exmode,
+  rc = iso7816_decipher (app_get_slot (app), exmode,
                          indata, indatalen, le_value, padind,
                          outdata, outdatalen);
   xfree (fixbuf);
@@ -5309,7 +5319,7 @@ gpg_error_t
 app_select_openpgp (app_t app)
 {
   static char const aid[] = { 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01 };
-  int slot = app->slot;
+  int slot = app_get_slot (app);
   gpg_error_t err;
   unsigned char *buffer;
   size_t buflen;
diff --git a/scd/app-sc-hsm.c b/scd/app-sc-hsm.c
index ab9400719..4b9f7fc03 100644
--- a/scd/app-sc-hsm.c
+++ b/scd/app-sc-hsm.c
@@ -483,7 +483,8 @@ read_ef_prkd (app_t app, unsigned short fid, prkdf_object_t *prkdresult,
   if (!fid)
     return gpg_error (GPG_ERR_NO_DATA); /* No private keys. */
 
-  err = select_and_read_binary (app->slot, fid, "PrKDF", &buffer, &buflen, 255);
+  err = select_and_read_binary (app_get_slot (app),
+                                fid, "PrKDF", &buffer, &buflen, 255);
   if (err)
     return err;
 
@@ -831,7 +832,7 @@ read_ef_prkd (app_t app, unsigned short fid, prkdf_object_t *prkdresult,
   xfree (buffer);
   buffer = NULL;
   buflen = 0;
-  err = select_and_read_binary (app->slot,
+  err = select_and_read_binary (app_get_slot (app),
                                 ((SC_HSM_EE_PREFIX << 8) | (fid & 0xFF)),
                                 "CertEF", &buffer, &buflen, 1);
   if (!err && buffer[0] == 0x30)
@@ -952,7 +953,8 @@ read_ef_cd (app_t app, unsigned short fid, cdf_object_t *result)
   if (!fid)
     return gpg_error (GPG_ERR_NO_DATA); /* No certificates. */
 
-  err = select_and_read_binary (app->slot, fid, "CDF", &buffer, &buflen, 255);
+  err = select_and_read_binary (app_get_slot (app), fid, "CDF",
+                                &buffer, &buflen, 255);
   if (err)
     return err;
 
@@ -1201,7 +1203,7 @@ read_serialno(app_t app)
   size_t n, objlen, hdrlen, chrlen;
   int class, tag, constructed, ndef;
 
-  err = select_and_read_binary (app->slot, 0x2F02, "EF.C_DevAut",
+  err = select_and_read_binary (app_get_slot (app), 0x2F02, "EF.C_DevAut",
                                 &buffer, &buflen, 512);
   if (err)
     return err;
@@ -1259,7 +1261,7 @@ read_meta (app_t app)
   if (err)
     return err;
 
-  err = list_ef (app->slot, &eflist, &eflistlen);
+  err = list_ef (app_get_slot (app), &eflist, &eflistlen);
   if (err)
     return err;
 
@@ -1453,7 +1455,7 @@ readcert_by_cdf (app_t app, cdf_object_t cdf,
       return 0;
     }
 
-  err = select_and_read_binary (app->slot, cdf->fid, "CD",
+  err = select_and_read_binary (app_get_slot (app), cdf->fid, "CD",
                                 &buffer, &buflen, 4096);
   if (err)
     {
@@ -1692,8 +1694,8 @@ verify_pin (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
   char *prompt;
   int sw;
 
-  sw = apdu_send_simple (app->slot, 0, 0x00, ISO7816_VERIFY, 0x00, 0x81,
-                         -1, NULL);
+  sw = apdu_send_simple (app_get_slot (app),
+                         0, 0x00, ISO7816_VERIFY, 0x00, 0x81, -1, NULL);
 
   if (sw == SW_SUCCESS)
     return 0;                   /* PIN already verified */
@@ -1718,7 +1720,7 @@ verify_pin (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
   prompt = "||Please enter the PIN";
 
   if (!opt.disable_pinpad
-      && !iso7816_check_pinpad (app->slot, ISO7816_VERIFY, &pininfo) )
+      && !iso7816_check_pinpad (app_get_slot (app), ISO7816_VERIFY, &pininfo) )
     {
       err = pincb (pincb_arg, prompt, NULL);
       if (err)
@@ -1727,7 +1729,7 @@ verify_pin (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
           return err;
         }
 
-      err = iso7816_verify_kp (app->slot, 0x81, &pininfo);
+      err = iso7816_verify_kp (app_get_slot (app), 0x81, &pininfo);
       pincb (pincb_arg, NULL, NULL);  /* Dismiss the prompt. */
     }
   else
@@ -1739,7 +1741,8 @@ verify_pin (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
           return err;
         }
 
-      err = iso7816_verify (app->slot, 0x81, pinvalue, strlen(pinvalue));
+      err = iso7816_verify (app_get_slot (app),
+                            0x81, pinvalue, strlen(pinvalue));
       xfree (pinvalue);
     }
   if (err)
@@ -1884,7 +1887,8 @@ do_sign (app_t app, ctrl_t ctrl, const char *keyidstr, int hashalgo,
   if (err)
     return err;
 
-  sw = apdu_send_le (app->slot, 1, 0x80, 0x68, prkdf->key_reference, algoid,
+  sw = apdu_send_le (app_get_slot (app),
+                     1, 0x80, 0x68, prkdf->key_reference, algoid,
                      cdsblklen, cdsblk, 0, outdata, outdatalen);
   return iso7816_map_sw (sw);
 }
@@ -2021,7 +2025,8 @@ do_decipher (app_t app, ctrl_t ctrl, const char *keyidstr,
   if (err)
     return err;
 
-  sw = apdu_send_le (app->slot, 1, 0x80, 0x62, prkdf->key_reference, 0x21,
+  sw = apdu_send_le (app_get_slot (app),
+                     1, 0x80, 0x62, prkdf->key_reference, 0x21,
                      p1blklen, p1blk, 0, &rspdata, &rspdatalen);
   err = iso7816_map_sw (sw);
   if (err)
@@ -2047,7 +2052,7 @@ do_decipher (app_t app, ctrl_t ctrl, const char *keyidstr,
 gpg_error_t
 app_select_sc_hsm (app_t app)
 {
-  int slot = app->slot;
+  int slot = app_get_slot (app);
   int rc;
 
   rc = iso7816_select_application (slot, sc_hsm_aid, sizeof sc_hsm_aid, 0);