diff --git a/dv/uvm/core_ibex/Makefile b/dv/uvm/core_ibex/Makefile
index b813af91..e5d9a371 100644
--- a/dv/uvm/core_ibex/Makefile
+++ b/dv/uvm/core_ibex/Makefile
@@ -417,29 +417,14 @@ rtl_tb_compile: $(OUT-DIR)rtl_sim/.rtl.tb_compile.stamp
 
 ###############################################################################
 # Run ibex RTL simulation with generated programs
-#
-# Because we compile a TB once rather than for each seed, we have to copy in
-# that directory before we start. We make this step (rather than actually
-# running the test) dependent on having the right variables. That way, we'll
-# correctly delete the sim directory and re-copy it if necessary.
-#
-# Note that the variables we depend on are instr-gen-build-vars-prereq.
-# We also depend on COV and WAVES, but these dependencies will come for free
-# from the dependency on the compiled TB.
-$(metadata)/.rtl.tb_compile.stamp: \
-  $(OUT-DIR)rtl_sim/.rtl.tb_compile.stamp \
-  $(instr-gen-build-vars-prereq) $(risc-dv-files)
-	rm -rf $(OUT-SEED)/rtl_sim
-	cp -r $(OUT-DIR)rtl_sim $(OUT-SEED)
-	@touch $@
 
 rtl-sim-dirs := $(addprefix $(OUT-SEED)/rtl_sim/,$(tests-and-seeds))
 rtl-sim-logs := $(addsuffix /sim.log,$(rtl-sim-dirs))
 
 $(rtl-sim-logs): \
-  $(OUT-SEED)/rtl_sim/%/sim.log:  \
-  $(metadata)/.rtl.tb_compile.stamp \
-  $(OUT-SEED)/instr_gen/%.bin       \
+  $(OUT-SEED)/rtl_sim/%/sim.log:          \
+  $(OUT-DIR)rtl_sim/.rtl.tb_compile.stamp \
+  $(OUT-SEED)/instr_gen/%.bin             \
   scripts/run-rtl.py
 	@echo Running RTL simulation at $@
 	$(verb)mkdir -p $(@D)
@@ -449,7 +434,8 @@ $(rtl-sim-logs): \
 	  --signature-addr $(SIGNATURE_ADDR)    \
 	  --test-dot-seed $*                    \
 	  --binary $(OUT-SEED)/instr_gen/$*.bin \
-	  --rtl-sim-dir $(OUT-SEED)/rtl_sim     \
+	  --rtl-sim-dir $(OUT-DIR)rtl_sim       \
+	  --out-dir $(OUT-SEED)/rtl_sim/$*      \
 	  --sim-opts "$(SIM_OPTS)"
 
 .PHONY: rtl_sim_run
diff --git a/dv/uvm/core_ibex/scripts/run-rtl.py b/dv/uvm/core_ibex/scripts/run-rtl.py
index f0cd98d7..4c064650 100755
--- a/dv/uvm/core_ibex/scripts/run-rtl.py
+++ b/dv/uvm/core_ibex/scripts/run-rtl.py
@@ -62,6 +62,7 @@ def main() -> int:
                         required=True)
     parser.add_argument('--binary', required=True)
     parser.add_argument('--rtl-sim-dir', required=True)
+    parser.add_argument('--out-dir', required=True)
     parser.add_argument('--sim-opts')
 
     args = parser.parse_args()
@@ -89,16 +90,15 @@ def main() -> int:
                          })
 
     # Specialize base_cmd for this specific test
-    test_sim_dir = os.path.join(args.rtl_sim_dir,
-                                '{}.{}'.format(testname, seed))
     test_cmd = get_test_sim_cmd(sim_cmd, entry,
-                                args.binary, seed, test_sim_dir)
+                                args.binary, seed, args.out_dir)
 
     # Run test_cmd (it's a string, so we have to call out to the shell to do
     # so). Note that we don't capture the success or failure of the subprocess:
     # if something goes horribly wrong, we assume we won't have a matching
     # trace.
-    sim_log = os.path.join(test_sim_dir, 'sim.log')
+    sim_log = os.path.join(args.out_dir, 'sim.log')
+    os.makedirs(args.out_dir, exist_ok=True)
     with open(sim_log, 'wb') as sim_fd:
         subprocess.run(test_cmd, shell=True, stdout=sim_fd, stderr=sim_fd)