t55xx detect/read/write/dump etc will fail if you set lf config to something. Moved the reset / restore of lf config to device side for T55XX readblock. t55xx sniff still obeys lf config since it uses lf sniff beneath.

armsrc/appmain.c

@@ -818,7 +818,6 @@ static void PacketReceived(PacketCommandNG *packet) {
             sample_config c;
             memcpy(&c, packet->data.asBytes, sizeof(sample_config));
             setSamplingConfig(&c);
-//            setSamplingConfig((sample_config *) packet->data.asBytes);
             break;
         }
         case CMD_LF_ACQ_RAW_ADC: {

armsrc/lfops.c

@@ -1999,6 +1999,12 @@ void T55xxReadBlock(uint8_t page, bool pwd_mode, bool brute_mem, uint8_t block,
     flags                |= (downlink_mode & 3) << 3;
     if (brute_mem) flags |= 0x0100;
 
+    sample_config old_config;
+    sample_config *curr_config = getSamplingConfig();
+    memcpy(&old_config, curr_config, sizeof(sample_config));
+    old_config.verbose = false;
+
+    setDefaultSamplingConfig();
 
     size_t samples = 12000;
 
@@ -2037,6 +2043,9 @@ void T55xxReadBlock(uint8_t page, bool pwd_mode, bool brute_mem, uint8_t block,
         reply_ng(CMD_LF_T55XX_READBL, PM3_SUCCESS, NULL, 0);
         LED_A_OFF();
     }
+
+    // reset back to old / save config
+    setSamplingConfig(&old_config);
 }
 
 

armsrc/lfsampling.c

@@ -28,7 +28,18 @@ Default LF config is set to:
     samples_to_skip = 0
     verbose = YES
     */
-static sample_config config = { 1, 8, 1, LF_DIVISOR_125, 0, 0, 1} ;
+
+static sample_config def_config = {
+        .decimation = 1,
+        .bits_per_sample = 8,
+        .averaging = 1,
+        .divisor = LF_DIVISOR_125,
+        .trigger_threshold = 0,
+        .samples_to_skip = 0,
+        .verbose = false,
+    };
+
+static sample_config config = { 1, 8, 1, LF_DIVISOR_125, 0, 0, true} ;
 
 // Holds bit packed struct of samples.
 static BitstreamOut data = {0, 0, 0};
@@ -57,6 +68,11 @@ void printSamples(void) {
     print_stack_usage();
 }
 
+
+void setDefaultSamplingConfig(void) {
+    setSamplingConfig(&def_config);
+}
+
 /**
  * Called from the USB-handler to set the sampling configuration
  * The sampling config is used for standard reading and sniffing.

armsrc/lfsampling.h

@@ -96,7 +96,7 @@ void LFSetupFPGAForADC(int divisor, bool reader_field);
  * @param sc
  */
 void setSamplingConfig(sample_config *sc);
-
+void setDefaultSamplingConfig(void);
 sample_config *getSamplingConfig(void);
 
 void printLFConfig(void);

client/src/cmdlft55xx.c

@@ -942,27 +942,6 @@ static int CmdT55xxDetect(const char *Cmd) {
     // detect called so clear data blocks
     T55x7_ClearAllBlockData();
 
-    // make sure decimate == 1
-    sample_config curr_lf_config;
-    memset(&curr_lf_config, 0, sizeof(sample_config));
-
-    res = lf_getconfig(&curr_lf_config);
-    if (res != PM3_SUCCESS) {
-        PrintAndLogEx(ERR, "failed to get current device LF config");
-        return res;
-    }
-    int8_t old_decimation = curr_lf_config.decimation;
-    if (curr_lf_config.decimation != 1) {
-        curr_lf_config.decimation = 1;
-        curr_lf_config.verbose = false;
-        res = lf_config(&curr_lf_config);
-        if (res != PM3_SUCCESS) {
-            PrintAndLogEx(ERR, "failed to set LF configuration decimation value to 1");
-            return res;
-        }
-    }
-
-
     // sanity check.
     if (SanityOfflineCheck(use_gb) != PM3_SUCCESS)
         return PM3_ESOFT;
@@ -1038,17 +1017,6 @@ static int CmdT55xxDetect(const char *Cmd) {
         PrintAndLogEx(WARNING, "Could not detect modulation automatically. Try setting it manually with " _YELLOW_("\'lf t55xx config\'"));
     }
 
-
-    if (old_decimation != curr_lf_config.decimation) {
-        curr_lf_config.decimation = old_decimation;
-        curr_lf_config.verbose = false;
-        res = lf_config(&curr_lf_config);
-        if (res != PM3_SUCCESS) {
-            PrintAndLogEx(ERR, "failed to restore LF configuration");
-            return res;
-        }
-    }
-
     return PM3_SUCCESS;
 }