diff --git a/dv/uvm/core_ibex/Makefile b/dv/uvm/core_ibex/Makefile
index 8d9541ec..7e6710f0 100644
--- a/dv/uvm/core_ibex/Makefile
+++ b/dv/uvm/core_ibex/Makefile
@@ -85,12 +85,6 @@ RUN-DIR   := $(OUT-DIR)run
 # get printed when VERBOSE.
 verb = $(if $(filter-out 0,$(VERBOSE)),,@)
 
-# Convert VERBOSE, COV, WAVE and COSIM to "store_true" arguments
-verb-arg  := $(if $(filter-out 0,$(VERBOSE)),--verbose,)
-cov-arg   := $(if $(call equal,$(COV),1),--en_cov,)
-wave-arg  := $(if $(call equal,$(WAVES),1),--en_wave,)
-cosim-arg := $(if $(call equal,$(COSIM),1),--en_cosim,)
-
 SHELL=/bin/bash
 
 export PRJ_DIR        := $(realpath ../../..)
@@ -175,6 +169,12 @@ FORCE:
 # Call it as $(call vars-prereq,X,TGT,VS)
 vars-prereq = $(if $(call vars-differ,$(call strip,$(1)),$(2),$(3)),FORCE,)
 
+# Convert VERBOSE, COV, WAVE and COSIM to "store_true" arguments
+verb-arg  := $(if $(filter-out 0,$(VERBOSE)),--verbose,)
+cov-arg   := $(if $(call equal,$(COV),1),--en_cov,)
+wave-arg  := $(if $(call equal,$(WAVES),1),--en_wave,)
+cosim-arg := $(if $(call equal,$(COSIM),1),--en_cosim,)
+
 ###############################################################################
 # Get a list of tests and seeds
 #
@@ -355,11 +355,12 @@ $(BUILD-DIR)/tb/.compile.stamp: \
   $(tb-compile-vars-prereq) $(all-verilog) $(risc-dv-files) \
   scripts/compile-tb.py yaml/rtl_simulation.yaml \
   | $(BUILD-DIR)
-	$(verb)scripts/compile-tb.py           \
-	  $(verb-arg)                          \
-	  --ibex-config $(IBEX_CONFIG)         \
-	  --output=$(BUILD-DIR)/tb             \
-	  --simulator=$(SIMULATOR)             \
+	$(verb)scripts/compile-tb.py             \
+	  $(verb-arg)                            \
+	  --ibex-config $(IBEX_CONFIG)           \
+	  --output=$(BUILD-DIR)/tb               \
+	  --shared-cov-dir=$(RUN-DIR)/shared_cov \
+	  --simulator=$(SIMULATOR)               \
 	  $(cov-arg) $(wave-arg) $(cosim-arg)
 	$(call dump-vars,$(tb-compile-vars-path),comp,$(tb-compile-var-deps))
 	@touch $@
@@ -376,14 +377,15 @@ $(rtl-sim-logs): \
   $(RUN-DIR)/%/rtl.log:           \
   $(BUILD-DIR)/tb/.compile.stamp $(RUN-DIR)/%/test.bin scripts/run-rtl.py
 	@echo Running RTL simulation at $@
-	$(verb)scripts/run-rtl.py               \
-	  --ibex-config $(IBEX_CONFIG)          \
-	  --simulator $(SIMULATOR)              \
-	  $(cov-arg) $(wave-arg)                \
-	  --signature-addr $(SIGNATURE_ADDR)    \
-	  --test-dot-seed $*                    \
-	  --binary $(RUN-DIR)/$*/test.bin       \
-	  --rtl-sim-dir $(BUILD-DIR)/tb         \
+	$(verb)scripts/run-rtl.py                \
+	  --ibex-config $(IBEX_CONFIG)           \
+	  --simulator $(SIMULATOR)               \
+	  --shared-cov-dir=$(RUN-DIR)/shared_cov \
+	  $(cov-arg) $(wave-arg)                 \
+	  --signature-addr $(SIGNATURE_ADDR)     \
+	  --test-dot-seed $*                     \
+	  --binary $(RUN-DIR)/$*/test.bin        \
+	  --rtl-sim-dir $(BUILD-DIR)/tb          \
 	  --out-dir $(@D)
 
 .PHONY: rtl_sim_run
diff --git a/dv/uvm/core_ibex/scripts/compile-tb.py b/dv/uvm/core_ibex/scripts/compile-tb.py
index 1f984bd2..c0e27516 100755
--- a/dv/uvm/core_ibex/scripts/compile-tb.py
+++ b/dv/uvm/core_ibex/scripts/compile-tb.py
@@ -19,6 +19,7 @@ def main() -> int:
 
     parser.add_argument('--ibex-config', required=True)
     parser.add_argument('--output', required=True)
+    parser.add_argument('--shared-cov-dir', required=True)
     parser.add_argument('--simulator', required=True)
     parser.add_argument('--en_cov', action='store_true')
     parser.add_argument('--en_wave', action='store_true')
@@ -47,6 +48,7 @@ def main() -> int:
                          {
                              'core_ibex': core_ibex,
                              'out': args.output,
+                             'shared_cov_dir': args.shared_cov_dir,
                              'cmp_opts': get_compile_opts(args.ibex_config,
                                                           args.simulator)
                          })
diff --git a/dv/uvm/core_ibex/scripts/merge-cov.py b/dv/uvm/core_ibex/scripts/merge-cov.py
index 76d60886..fd2dd681 100755
--- a/dv/uvm/core_ibex/scripts/merge-cov.py
+++ b/dv/uvm/core_ibex/scripts/merge-cov.py
@@ -30,10 +30,10 @@ def find_cov_dirs(start_dir: str, simulator: str) -> Set[str]:
             if file.endswith(".ucd") and simulator == 'xlm':
                 logging.info("Found coverage database (ucd) at %s" % path)
                 cov_dirs.add(path)
-            if vdb_dir_name in dirs and simulator == 'vcs':
-                vdb_path = os.path.join(path, vdb_dir_name)
-                logging.info("Found coverage database (vdb) at %s" % vdb_path)
-                cov_dirs.add(vdb_path)
+        if vdb_dir_name in dirs and simulator == 'vcs':
+            vdb_path = os.path.join(path, vdb_dir_name)
+            logging.info("Found coverage database (vdb) at %s" % vdb_path)
+            cov_dirs.add(vdb_path)
 
     return cov_dirs
 
@@ -74,10 +74,12 @@ def merge_cov_xlm(cov_dir: str, verbose: bool, cov_dirs: Set[str]) -> int:
     # that handles them)
     xlm_cov_dirs['cov_db_dirs'] = ' '.join(cov_dir_parents)
 
-    xlm_env = os.environ | xlm_cov_dirs
+    xlm_env = os.environ.copy()
+    xlm_env.update(xlm_cov_dirs)
 
     # First do the merge
     imc_cmd = ["imc", "-64bit", "-licqueue"]
+    os.makedirs(merge_dir, exist_ok=True)
     cov_merge_tcl = os.path.join(xcelium_scripts, "cov_merge.tcl")
     merge_ret = run_one(verbose,
                         imc_cmd + ["-exec", cov_merge_tcl,
diff --git a/dv/uvm/core_ibex/scripts/run-rtl.py b/dv/uvm/core_ibex/scripts/run-rtl.py
index a07cedbf..2bc2c346 100755
--- a/dv/uvm/core_ibex/scripts/run-rtl.py
+++ b/dv/uvm/core_ibex/scripts/run-rtl.py
@@ -55,6 +55,7 @@ def get_test_sim_cmd(base_cmd, test, binary, seed, sim_dir):
 def main() -> int:
     parser = argparse.ArgumentParser()
     parser.add_argument('--ibex-config', required=True)
+    parser.add_argument('--shared-cov-dir', required=True)
     parser.add_argument('--simulator', required=True)
     parser.add_argument("--en_cov", action='store_true')
     parser.add_argument("--en_wave", action='store_true')
@@ -85,6 +86,7 @@ def main() -> int:
     sim_cmd = subst_vars(base_cmd,
                          {
                              'out': args.rtl_sim_dir,
+                             'shared_cov_dir': args.shared_cov_dir,
                              'sim_opts': sim_opts,
                              'cwd': _CORE_IBEX,
                          })
diff --git a/dv/uvm/core_ibex/yaml/rtl_simulation.yaml b/dv/uvm/core_ibex/yaml/rtl_simulation.yaml
index 98f70aa4..2748ee50 100644
--- a/dv/uvm/core_ibex/yaml/rtl_simulation.yaml
+++ b/dv/uvm/core_ibex/yaml/rtl_simulation.yaml
@@ -39,7 +39,7 @@
       -cm_tgl structarr
       -cm_report noinitial
       -cm_seqnoconst
-      -cm_dir <out>/test.vdb
+      -cm_dir <shared_cov_dir>/test.vdb
       -cm_hier cover.cfg
     wave_opts: >
       -debug_access+all -ucli -do vcs.tcl
@@ -61,10 +61,10 @@
           +cosim_log_file=<sim_dir>/spike_cosim.log
     cov_opts: >
       -cm line+tgl+assert+fsm+branch
-      -cm_dir <out>/test.vdb
+      -cm_dir <shared_cov_dir>/test.vdb
       -cm_log /dev/null
       -assert nopostproc
-      -cm_name test_<test_name>_<iteration>
+      -cm_name test_<test_name>_<seed>
       +enable_ibex_fcov=1
     wave_opts: >
       -ucli -do <cwd>/vcs.tcl
@@ -186,9 +186,9 @@
            <cov_opts>
            <wave_opts>
     cov_opts: >
-      -covmodeldir <out>/coverage/default/<test_name>.<seed>
-      -covworkdir <out>/coverage
-      -covscope default
+      -covmodeldir <sim_dir>/coverage
+      -covworkdir <sim_dir>
+      -covscope coverage
       -covtest <test_name>.<seed>
       +enable_ibex_fcov=1
     wave_opts: >