diff --git a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
index ccee11d37e..e297c16c62 100644
--- a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
+++ b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c
@@ -5266,7 +5266,9 @@ int get_FeedbackDisabled(NR_DownlinkHARQ_FeedbackDisabled_r17_t *downlinkHARQ_Fe
   return (downlinkHARQ_FeedbackDisabled_r17->buf[byte_index] >> (7 - bit_index)) & 1;
 }
 
-int nr_get_prach_mu(const NR_MsgA_ConfigCommon_r16_t *msgacc, const NR_RACH_ConfigCommon_t *rach_ConfigCommon)
+int nr_get_prach_or_ul_mu(const NR_MsgA_ConfigCommon_r16_t *msgacc,
+                          const NR_RACH_ConfigCommon_t *rach_ConfigCommon,
+                          const int ul_mu)
 {
   int mu;
 
@@ -5278,7 +5280,8 @@ int nr_get_prach_mu(const NR_MsgA_ConfigCommon_r16_t *msgacc, const NR_RACH_Conf
     // Choose Subcarrier Spacing of configuration file of 4-Step
     mu = *rach_ConfigCommon->msg1_SubcarrierSpacing;
   } else
-    AssertFatal(false, "PRACH subcarrier spacing mandatory present for L139, not supported otherwise\n");
+    // Return invalid UL mu
+    mu = ul_mu;
 
   return mu;
 }
diff --git a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h
index cb0d5a9611..923585205a 100644
--- a/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h
+++ b/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h
@@ -334,6 +334,6 @@ int get_nrofHARQ_ProcessesForPDSCH(const NR_UE_ServingCell_Info_t *sc_info);
 
 int get_nrofHARQ_ProcessesForPUSCH(const NR_UE_ServingCell_Info_t *sc_info);
 
-int nr_get_prach_mu(const NR_MsgA_ConfigCommon_r16_t *msgacc, const NR_RACH_ConfigCommon_t *rach_ConfigCommon);
+int nr_get_prach_or_ul_mu(const NR_MsgA_ConfigCommon_r16_t *msgacc, const NR_RACH_ConfigCommon_t *rach_ConfigCommon, const int ul_mu);
 
 #endif
diff --git a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
index e3407c95b3..da72d9d41a 100644
--- a/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
+++ b/openair2/LAYER2/NR_MAC_UE/nr_ue_scheduler.c
@@ -1849,7 +1849,8 @@ static void build_ro_list(NR_UE_MAC_INST_t *mac)
   int unpaired = mac->phy_config.config_req.cell_config.frame_duplex_type;
 
   const int64_t *prach_config_info_p = get_prach_config_info(mac->frequency_range, config_index, unpaired);
-  int mu = nr_get_prach_mu(mac->current_UL_BWP->msgA_ConfigCommon_r16, setup);
+  const int ul_mu = mac->current_UL_BWP->scs;
+  const int mu = nr_get_prach_or_ul_mu(mac->current_UL_BWP->msgA_ConfigCommon_r16, setup, ul_mu);
 
   // Identify the proper PRACH Configuration Index table according to the operating frequency
   LOG_D(NR_MAC,"mu = %u, PRACH config index  = %u, unpaired = %u\n", mu, config_index, unpaired);
diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
index d4b9c973ee..4fe4574209 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c
@@ -92,7 +92,8 @@ static int16_t ssb_index_from_prach(module_id_t module_idP,
   NR_MsgA_ConfigCommon_r16_t *msgacc = NULL;
   if (scc->uplinkConfigCommon->initialUplinkBWP->ext1 && scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16)
     msgacc = scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16->choice.setup;
-  int mu = nr_get_prach_mu(msgacc, rach_ConfigCommon);
+  const int ul_mu = scc->uplinkConfigCommon->frequencyInfoUL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
+  const int mu = nr_get_prach_or_ul_mu(msgacc, rach_ConfigCommon, ul_mu);
 
   get_nr_prach_info_from_index(config_index,
 			       (int)frameP,
@@ -199,7 +200,8 @@ void find_SSB_and_RO_available(gNB_MAC_INST *nrmac)
   NR_MsgA_ConfigCommon_r16_t *msgacc = NULL;
   if (scc->uplinkConfigCommon->initialUplinkBWP->ext1 && scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16)
     msgacc = scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16->choice.setup;
-  int mu = nr_get_prach_mu(msgacc, rach_ConfigCommon);
+  const int ul_mu = scc->uplinkConfigCommon->frequencyInfoUL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
+  const int mu = nr_get_prach_or_ul_mu(msgacc, rach_ConfigCommon, ul_mu);
 
   // prach is scheduled according to configuration index and tables 6.3.3.2.2 to 6.3.3.2.4
   get_nr_prach_occasion_info_from_index(config_index,
@@ -366,7 +368,6 @@ void schedule_nr_prach(module_id_t module_idP, frame_t frameP, sub_frame_t slotP
   NR_MsgA_ConfigCommon_r16_t *msgacc = NULL;
   if (scc->uplinkConfigCommon->initialUplinkBWP->ext1 && scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16)
     msgacc = scc->uplinkConfigCommon->initialUplinkBWP->ext1->msgA_ConfigCommon_r16->choice.setup;
-  int mu = nr_get_prach_mu(msgacc, rach_ConfigCommon);
   int slots_frame = gNB->frame_structure.numb_slots_frame;
   int index = ul_buffer_index(frameP, slotP, slots_frame, gNB->UL_tti_req_ahead_size);
   nfapi_nr_ul_tti_request_t *UL_tti_req = &RC.nrmac[module_idP]->UL_tti_req_ahead[0][index];
@@ -385,6 +386,8 @@ void schedule_nr_prach(module_id_t module_idP, frame_t frameP, sub_frame_t slotP
     int bwp_start = NRRIV2PRBOFFSET(scc->uplinkConfigCommon->initialUplinkBWP->genericParameters.locationAndBandwidth, MAX_BWP_SIZE);
 
     uint8_t fdm = cfg->prach_config.num_prach_fd_occasions.value;
+    const int ul_mu = scc->uplinkConfigCommon->frequencyInfoUL->scs_SpecificCarrierList.list.array[0]->subcarrierSpacing;
+    const int mu = nr_get_prach_or_ul_mu(msgacc, rach_ConfigCommon, ul_mu);
     // prach is scheduled according to configuration index and tables 6.3.3.2.2 to 6.3.3.2.4
     if (get_nr_prach_info_from_index(config_index,
                                      (int)frameP,