diff --git a/armsrc/appmain.c b/armsrc/appmain.c
index fcd667c52..a2b1e9f10 100644
--- a/armsrc/appmain.c
+++ b/armsrc/appmain.c
@@ -2391,15 +2391,15 @@ static void PacketReceived(PacketCommandNG *packet) {
             // arg2 = BigBuf tracelen
             //Dbprintf("transfer to client parameters: %" PRIu32 " | %" PRIu32 " | %" PRIu32, startidx, numofbytes, packet->oldarg[2]);
 
-            for (size_t i = 0; i < numofbytes; i += PM3_CMD_DATA_SIZE) {
-                size_t len = MIN((numofbytes - i), PM3_CMD_DATA_SIZE);
-                int result = reply_old(CMD_DOWNLOADED_BIGBUF, i, len, BigBuf_get_traceLen(), mem + startidx + i, len);
+            for (size_t offset = 0; offset < numofbytes; offset += PM3_CMD_DATA_SIZE) {
+                size_t len = MIN((numofbytes - offset), PM3_CMD_DATA_SIZE);
+                int result = reply_old(CMD_DOWNLOADED_BIGBUF, offset, len, BigBuf_get_traceLen(), &mem[startidx + offset], len);
                 if (result != PM3_SUCCESS)
-                    Dbprintf("transfer to client failed ::  | bytes between %d - %d (%d) | result: %d", i, i + len, len, result);
+                    Dbprintf("transfer to client failed ::  | bytes between %d - %d (%d) | result: %d", offset, offset + len, len, result);
             }
             // Trigger a finish downloading signal with an ACK frame
             // arg0 = status of download transfer
-            reply_mix(CMD_ACK, 1, 0, 0, 0, 0);
+            reply_mix(CMD_ACK, 1, 0, BigBuf_get_traceLen(), NULL, 0);
             LED_B_OFF();
             break;
         }
diff --git a/client/src/cmddata.c b/client/src/cmddata.c
index 060df0b5a..53d93b4ca 100644
--- a/client/src/cmddata.c
+++ b/client/src/cmddata.c
@@ -29,6 +29,7 @@
 #include "graph.h"               // for graph data
 #include "comms.h"
 #include "lfdemod.h"             // for demod code
+#include "cmdlf.h"               // for lf_getconfig
 #include "loclass/cipherutils.h" // for decimating samples in getsamples
 #include "cmdlfem410x.h"         // askem410xdecode
 #include "fileutils.h"           // searchFile
@@ -1875,13 +1876,13 @@ int getSamplesEx(uint32_t start, uint32_t end, bool verbose, bool ignore_lf_conf
 
     uint8_t bits_per_sample = 8;
 
-    // Old devices without this feature would send 0 at arg[0]
-    if (resp.oldarg[0] > 0 && (ignore_lf_config == false)) {
-        sample_config *sc = (sample_config *) resp.data.asBytes;
+    if (IfPm3Lf() && ignore_lf_config == false) {
+        sample_config sc;
+        lf_getconfig(&sc);
         if (verbose) {
-            PrintAndLogEx(INFO, "Samples @ " _YELLOW_("%d") " bits/smpl, decimation 1:%d ", sc->bits_per_sample, sc->decimation);
+            PrintAndLogEx(INFO, "Samples @ " _YELLOW_("%d") " bits/smpl, decimation 1:%d ", sc.bits_per_sample, sc.decimation);
         }
-        bits_per_sample = sc->bits_per_sample;
+        bits_per_sample = sc.bits_per_sample;
     }
 
     return getSamplesFromBufEx(got, n, bits_per_sample, verbose);;