diff --git a/srsenb/hdr/stack/mac/nr/sched_nr_cfg.h b/srsenb/hdr/stack/mac/nr/sched_nr_cfg.h
index b2295c2fc..be7e2657c 100644
--- a/srsenb/hdr/stack/mac/nr/sched_nr_cfg.h
+++ b/srsenb/hdr/stack/mac/nr/sched_nr_cfg.h
@@ -15,10 +15,11 @@
 
 #include "sched_nr_interface.h"
 #include "sched_nr_rb.h"
+#include "srsenb/hdr/common/common_enb.h"
 
 namespace srsenb {
 
-const static size_t SCHED_NR_MAX_USERS     = 4;
+const static size_t SCHED_NR_MAX_USERS     = SRSENB_MAX_UES;
 const static size_t SCHED_NR_NOF_SUBFRAMES = 10;
 const static size_t SCHED_NR_NOF_HARQS     = 16;
 static const size_t MAX_NOF_AGGR_LEVELS    = 5;
diff --git a/srsenb/hdr/stack/mac/nr/sched_nr_ue.h b/srsenb/hdr/stack/mac/nr/sched_nr_ue.h
index 044d10fdd..4b1ab12bf 100644
--- a/srsenb/hdr/stack/mac/nr/sched_nr_ue.h
+++ b/srsenb/hdr/stack/mac/nr/sched_nr_ue.h
@@ -114,8 +114,8 @@ private:
   ue_cfg_t ue_cfg;
 };
 
-using ue_map_t      = srsran::static_circular_map<uint16_t, std::unique_ptr<ue>, SCHED_NR_MAX_USERS>;
-using slot_ue_map_t = srsran::static_circular_map<uint16_t, slot_ue, SCHED_NR_MAX_USERS>;
+using ue_map_t      = rnti_map_t<std::unique_ptr<ue> >;
+using slot_ue_map_t = rnti_map_t<slot_ue>;
 
 } // namespace sched_nr_impl
 
diff --git a/srsenb/hdr/stack/mac/nr/sched_nr_worker.h b/srsenb/hdr/stack/mac/nr/sched_nr_worker.h
index fb739f6fd..2dc4c8141 100644
--- a/srsenb/hdr/stack/mac/nr/sched_nr_worker.h
+++ b/srsenb/hdr/stack/mac/nr/sched_nr_worker.h
@@ -101,7 +101,7 @@ public:
   }
 
 private:
-  void update_ue_db(slot_point slot_tx, bool update_ca_users);
+  void update_ue_db(slot_point slot_tx, bool locked_context);
 
   bool save_sched_result(slot_point pdcch_slot, uint32_t cc, dl_sched_res_t& dl_res, ul_sched_t& ul_res);
 
diff --git a/srsenb/src/stack/mac/nr/sched_nr.cc b/srsenb/src/stack/mac/nr/sched_nr.cc
index 721b18a66..7bfcdd521 100644
--- a/srsenb/src/stack/mac/nr/sched_nr.cc
+++ b/srsenb/src/stack/mac/nr/sched_nr.cc
@@ -98,7 +98,12 @@ void sched_nr::ue_cfg(uint16_t rnti, const ue_cfg_t& uecfg)
 void sched_nr::ue_cfg_impl(uint16_t rnti, const ue_cfg_t& uecfg)
 {
   if (not ue_db.contains(rnti)) {
-    ue_db.insert(rnti, std::unique_ptr<ue>(new ue{rnti, uecfg, cfg}));
+    auto ret = ue_db.insert(rnti, std::unique_ptr<ue>(new ue{rnti, uecfg, cfg}));
+    if (ret.has_value()) {
+      logger.info("SCHED: New user rnti=0x%x, cc=%d", rnti, cfg.cells[0].cc);
+    } else {
+      logger.error("SCHED: Failed to create new user rnti=0x%x", rnti);
+    }
   } else {
     ue_db[rnti]->set_cfg(uecfg);
   }
diff --git a/srsenb/src/stack/mac/nr/sched_nr_ue.cc b/srsenb/src/stack/mac/nr/sched_nr_ue.cc
index f14388166..a0bb2177b 100644
--- a/srsenb/src/stack/mac/nr/sched_nr_ue.cc
+++ b/srsenb/src/stack/mac/nr/sched_nr_ue.cc
@@ -140,12 +140,7 @@ slot_ue ue::try_reserve(slot_point pdcch_slot, uint32_t cc)
     return slot_ue();
   }
 
-  slot_ue sfu = carriers[cc]->try_reserve(pdcch_slot, cfg(), dl_pending_bytes, ul_pending_bytes);
-  if (sfu.empty()) {
-    return slot_ue();
-  }
-
-  return sfu;
+  return carriers[cc]->try_reserve(pdcch_slot, cfg(), dl_pending_bytes, ul_pending_bytes);
 }
 
 } // namespace sched_nr_impl
diff --git a/srsenb/src/stack/mac/nr/sched_nr_worker.cc b/srsenb/src/stack/mac/nr/sched_nr_worker.cc
index f0c682c16..954cc59f2 100644
--- a/srsenb/src/stack/mac/nr/sched_nr_worker.cc
+++ b/srsenb/src/stack/mac/nr/sched_nr_worker.cc
@@ -147,20 +147,21 @@ void sched_worker_manager::enqueue_cc_event(uint32_t cc, srsran::move_callback<v
 /**
  * Update UEs state that is non-CC specific (e.g. SRs, buffer status, UE configuration)
  * @param slot_tx
- * @param update_ca_users to update only UEs with CA enabled or not
+ * @param locked_context to update only UEs with CA enabled or not
  */
-void sched_worker_manager::update_ue_db(slot_point slot_tx, bool update_ca_users)
+void sched_worker_manager::update_ue_db(slot_point slot_tx, bool locked_context)
 {
   // process non-cc specific feedback if pending (e.g. SRs, buffer updates, UE config)
   for (ue_event_t& ev : slot_events) {
-    if (not ue_db.contains(ev.rnti) or ue_db[ev.rnti]->has_ca() == update_ca_users) {
+    if ((locked_context and not ue_db.contains(ev.rnti)) or
+        (ue_db.contains(ev.rnti) and ue_db[ev.rnti]->has_ca() == locked_context)) {
       ev.callback();
     }
   }
 
   // prepare UEs internal state for new slot
   for (auto& u : ue_db) {
-    if (u.second->has_ca() == update_ca_users) {
+    if (u.second->has_ca() == locked_context) {
       u.second->new_slot(slot_tx);
     }
   }