diff --git a/client/cmdflashmem.c b/client/cmdflashmem.c
index fd8cf0554..cbf336773 100644
--- a/client/cmdflashmem.c
+++ b/client/cmdflashmem.c
@@ -280,11 +280,13 @@ static int CmdFlashMemLoad(const char *Cmd) {
     //Send to device
     uint32_t bytes_sent = 0;
     uint32_t bytes_remaining = datalen;
-
     while (bytes_remaining > 0) {
         uint32_t bytes_in_packet = MIN(FLASH_MEM_BLOCK_SIZE, bytes_remaining);
 
         clearCommandBuffer();
+        if (bytes_remaining > bytes_in_packet)
+            // fast push mode
+            conn.block_after_ACK = true;
         SendCommandOLD(CMD_FLASHMEM_WRITE, start_index + bytes_sent, bytes_in_packet, 0, data + bytes_sent, bytes_in_packet);
 
         bytes_remaining -= bytes_in_packet;
@@ -293,9 +295,11 @@ static int CmdFlashMemLoad(const char *Cmd) {
         PacketResponseNG resp;
         if (!WaitForResponseTimeout(CMD_ACK, &resp, 2000)) {
             PrintAndLogEx(WARNING, "timeout while waiting for reply.");
+            conn.block_after_ACK = false;
             free(data);
             return PM3_ETIMEOUT;
         }
+        conn.block_after_ACK = false;
 
         uint8_t isok  = resp.oldarg[0] & 0xFF;
         if (!isok) {
diff --git a/client/comms.c b/client/comms.c
index 4501326c1..4ae05fc82 100644
--- a/client/comms.c
+++ b/client/comms.c
@@ -24,7 +24,7 @@ bool send_with_crc_on_fpc = true;
 // "Session" flag, to tell via which interface next msgs should be sent: USB or FPC USART
 bool send_via_fpc = false;
 
-static communication_arg_t conn;
+communication_arg_t conn;
 
 static pthread_t USB_communication_thread;
 //static pthread_t FPC_communication_thread;
@@ -476,7 +476,7 @@ __attribute__((force_align_arg_pointer))
 
         if (connection->block_after_ACK) {
             // if we just received an ACK, wait here until a new command is to be transmitted
-            // This is only working on OLD frames, and only used by flasher
+            // This is only working on OLD frames, and only used by flasher and flashmem
             if (ACK_received) {
                 while (!txBuffer_pending) {
                     pthread_cond_wait(&txBufferSig, &txBufferMutex);
diff --git a/client/comms.h b/client/comms.h
index c70a67c51..b3be16b1a 100644
--- a/client/comms.h
+++ b/client/comms.h
@@ -49,6 +49,7 @@ extern bool send_with_crc_on_usb;
 extern bool send_with_crc_on_fpc;
 // "Session" flag, to tell via which interface next msgs are sent: USB or FPC USART
 extern bool send_via_fpc;
+extern communication_arg_t conn;
 
 void SetOffline(bool value);
 bool IsOffline(void);