diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
index 7b010ad5bc..6ffdce88f0 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
@@ -2126,7 +2126,7 @@ static void nr_generate_Msg4_MsgB(module_id_t module_idP,
 
     harq->tb_size = tb_size;
 
-    uint8_t *buf = (uint8_t *) harq->transportBlock;
+    uint8_t *buf = allocate_transportBlock_buffer(&harq->transportBlock, tb_size);
     // Bytes to be transmitted
     if (harq->round == 0) {
       uint16_t mac_pdu_length = 0;
@@ -2206,11 +2206,11 @@ static void nr_generate_Msg4_MsgB(module_id_t module_idP,
     }
 
     T(T_GNB_MAC_DL_PDU_WITH_DATA, T_INT(module_idP), T_INT(CC_id), T_INT(ra->rnti),
-      T_INT(frameP), T_INT(slotP), T_INT(current_harq_pid), T_BUFFER(harq->transportBlock, harq->tb_size));
+      T_INT(frameP), T_INT(slotP), T_INT(current_harq_pid), T_BUFFER(harq->transportBlock.buf, harq->tb_size));
 
     // DL TX request
     nfapi_nr_pdu_t *tx_req = &TX_req->pdu_list[TX_req->Number_of_PDUs];
-    memcpy(tx_req->TLVs[0].value.direct, harq->transportBlock, sizeof(uint8_t) * harq->tb_size);
+    memcpy(tx_req->TLVs[0].value.direct, harq->transportBlock.buf, sizeof(uint8_t) * harq->tb_size);
     tx_req->PDU_index = pduindex;
     tx_req->num_TLV = 1;
     tx_req->TLVs[0].length =  harq->tb_size;
diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
index ce5bbfe9fd..48a72b527b 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
@@ -1280,12 +1280,12 @@ void nr_schedule_ue_spec(module_id_t module_id,
                   UE->rnti,
                   current_harq_pid);
       T(T_GNB_MAC_RETRANSMISSION_DL_PDU_WITH_DATA, T_INT(module_id), T_INT(CC_id), T_INT(rnti),
-        T_INT(frame), T_INT(slot), T_INT(current_harq_pid), T_INT(harq->round), T_BUFFER(harq->transportBlock, TBS));
+        T_INT(frame), T_INT(slot), T_INT(current_harq_pid), T_INT(harq->round), T_BUFFER(harq->transportBlock.buf, TBS));
       UE->mac_stats.dl.total_rbs_retx += sched_pdsch->rbSize;
       gNB_mac->mac_stats.used_prb_aggregate += sched_pdsch->rbSize;
     } else { /* initial transmission */
       LOG_D(NR_MAC, "Initial HARQ transmission in %d.%d\n", frame, slot);
-      uint8_t *buf = (uint8_t *) harq->transportBlock;
+      uint8_t *buf = allocate_transportBlock_buffer(&harq->transportBlock, TBS);
       /* first, write all CEs that might be there */
       int written = nr_write_ce_dlsch_pdu(module_id,
                                           sched_ctrl,
@@ -1420,7 +1420,7 @@ void nr_schedule_ue_spec(module_id_t module_id,
       }
 
       T(T_GNB_MAC_DL_PDU_WITH_DATA, T_INT(module_id), T_INT(CC_id), T_INT(rnti),
-        T_INT(frame), T_INT(slot), T_INT(current_harq_pid), T_BUFFER(harq->transportBlock, TBS));
+        T_INT(frame), T_INT(slot), T_INT(current_harq_pid), T_BUFFER(harq->transportBlock.buf, TBS));
     }
 
     const int ntx_req = TX_req->Number_of_PDUs;
@@ -1429,7 +1429,7 @@ void nr_schedule_ue_spec(module_id_t module_id,
     tx_req->num_TLV = 1;
     tx_req->TLVs[0].length = TBS;
     tx_req->PDU_length = compute_PDU_length(tx_req->num_TLV, tx_req->TLVs[0].length);
-    memcpy(tx_req->TLVs[0].value.direct, harq->transportBlock, TBS);
+    memcpy(tx_req->TLVs[0].value.direct, harq->transportBlock.buf, TBS);
     TX_req->Number_of_PDUs++;
     TX_req->SFN = frame;
     TX_req->Slot = slot;
diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c
index 708337640c..ec243fcd86 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c
@@ -2079,12 +2079,35 @@ void delete_nr_ue_data(NR_UE_info_t *UE, NR_COMMON_channels_t *ccPtr, uid_alloca
   destroy_nr_list(&sched_ctrl->available_ul_harq);
   destroy_nr_list(&sched_ctrl->feedback_ul_harq);
   destroy_nr_list(&sched_ctrl->retrans_ul_harq);
+  for (int i = 0; i < NR_MAX_HARQ_PROCESSES; ++i)
+    free_transportBlock_buffer(&sched_ctrl->harq_processes[i].transportBlock);
   free_sched_pucch_list(sched_ctrl);
   uid_linear_allocator_free(uia, UE->uid);
   LOG_I(NR_MAC, "Remove NR rnti 0x%04x\n", UE->rnti);
   free(UE);
 }
 
+#define TB_SINGLE_LAYER (32 * 1024)
+uint8_t *allocate_transportBlock_buffer(byte_array_t *tb, uint32_t needed)
+{
+  DevAssert(needed > 0);
+  if (tb->buf != NULL && needed <= tb->len)
+    return tb->buf; // nothing to do, current is enough
+
+  uint32_t size = TB_SINGLE_LAYER;
+  while (needed > size)
+    size *= 2;
+  LOG_D(NR_MAC, "allocating new TB block of size %d\n", size);
+  free(tb->buf);
+  tb->buf = malloc_or_fail(size);
+  tb->len = size;
+  return tb->buf;
+}
+
+void free_transportBlock_buffer(byte_array_t *tb)
+{
+  free_byte_array(*tb);
+}
 
 void set_max_fb_time(NR_UE_UL_BWP_t *UL_BWP, const NR_UE_DL_BWP_t *DL_BWP)
 {
diff --git a/openair2/LAYER2/NR_MAC_gNB/mac_proto.h b/openair2/LAYER2/NR_MAC_gNB/mac_proto.h
index d8c876439b..46deef46e8 100644
--- a/openair2/LAYER2/NR_MAC_gNB/mac_proto.h
+++ b/openair2/LAYER2/NR_MAC_gNB/mac_proto.h
@@ -381,6 +381,9 @@ void handle_nr_ul_harq(const int CC_idP,
                        sub_frame_t slot,
                        const nfapi_nr_crc_t *crc_pdu);
 
+uint8_t *allocate_transportBlock_buffer(byte_array_t *tb, uint32_t needed);
+void free_transportBlock_buffer(byte_array_t *tb);
+
 void handle_nr_srs_measurements(const module_id_t module_id,
                                 const frame_t frame,
                                 const sub_frame_t slot,
diff --git a/openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h b/openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h
index c94f64dfef..bb1fba0fe8 100644
--- a/openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h
+++ b/openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h
@@ -44,6 +44,7 @@
 #include <pthread.h>
 #include "common/utils/ds/seq_arr.h"
 #include "common/utils/nr/nr_common.h"
+#include "common/utils/ds/byte_array.h"
 
 #define NR_SCHED_LOCK(lock)                                        \
   do {                                                             \
@@ -481,10 +482,9 @@ typedef struct NR_UE_harq {
   uint16_t feedback_frame;
   uint16_t feedback_slot;
 
-  /* Transport block to be sent using this HARQ process, its size is in
-   * sched_pdsch */
-  uint32_t transportBlock[38016]; // valid up to 4 layers
-  uint32_t tb_size;
+  /* Transport block to be sent using this HARQ process */
+  byte_array_t transportBlock;
+  uint32_t tb_size;  // size of currently stored TB
 
   /// sched_pdsch keeps information on MCS etc used for the initial transmission
   NR_sched_pdsch_t sched_pdsch;