diff --git a/armsrc/epa.c b/armsrc/epa.c
index 2a0025610..b2a1b5ec5 100644
--- a/armsrc/epa.c
+++ b/armsrc/epa.c
@@ -22,10 +22,12 @@
 #include "commonutil.h"
 #include "ticks.h"
 
+#ifdef WITH_ISO14443a
 // Protocol and Parameter Selection Request for ISO 14443 type A cards
 // use regular (1x) speed in both directions
 // CRC is already included
 static const uint8_t pps[] = {0xD0, 0x11, 0x00, 0x52, 0xA6};
+#endif
 
 // APDUs for communication with German Identification Card
 
@@ -116,9 +118,25 @@ static char iso_type = 0;
 static int EPA_APDU(uint8_t *apdu, size_t length, uint8_t *response, uint16_t respmaxlen) {
     switch (iso_type) {
         case 'a':
+#ifdef WITH_ISO14443a
             return iso14_apdu(apdu, (uint16_t) length, false, response, NULL);
+#else
+            (void) apdu;
+            (void) length;
+            (void) response;
+            (void) respmaxlen;
+            return PM3_ENOTIMPL;
+#endif
         case 'b':
+#ifdef WITH_ISO14443b
             return iso14443b_apdu(apdu, length, false, response, respmaxlen, NULL);
+#else
+            (void) apdu;
+            (void) length;
+            (void) response;
+            (void) respmaxlen;
+            return PM3_ENOTIMPL;
+#endif
         default:
             return 0;
     }
@@ -522,7 +540,10 @@ void EPA_PACE_Replay(PacketCommandNG *c) {
 //-----------------------------------------------------------------------------
 int EPA_Setup(void) {
 
+#ifdef WITH_ISO14443a
+{
     // first, look for type A cards
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
     // power up the field
     iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
     iso14a_card_select_t card_a_info;
@@ -541,20 +562,24 @@ int EPA_Setup(void) {
         iso_type = 'a';
         return 0;
     }
-
-    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-
+}
+#endif
+#ifdef WITH_ISO14443b
+{
     // if we're here, there is no type A card, so we look for type B
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
     // power up the field
     iso14443b_setup();
     iso14b_card_select_t card_b_info;
-    return_code = iso14443b_select_card(&card_b_info);
+    int return_code = iso14443b_select_card(&card_b_info);
 
     if (return_code == 0) {
         Dbprintf("ISO 14443 Type B");
         iso_type = 'b';
         return 0;
     }
+}
+#endif
     Dbprintf("No card found");
     return 1;
 }
diff --git a/doc/md/Use_of_Proxmark/4_Advanced-compilation-parameters.md b/doc/md/Use_of_Proxmark/4_Advanced-compilation-parameters.md
index a61fcaf10..7b4ae12d4 100644
--- a/doc/md/Use_of_Proxmark/4_Advanced-compilation-parameters.md
+++ b/doc/md/Use_of_Proxmark/4_Advanced-compilation-parameters.md
@@ -141,6 +141,8 @@ SKIP_FELICA=1
 ```
 Situation might change when the firmware is growing of course, requiring to skip more elements.
 
+Last note: if you skip a tech, be careful not to use a standalone mode which requires that same tech, else the firmware size reduction won't be much.
+
 ## Next step
 
 See [Compilation instructions](/doc/md/Use_of_Proxmark/0_Compilation-Instructions.md)