diff --git a/kernel/Makefile b/kernel/Makefile
index 02221281..2782b1b2 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -913,7 +913,10 @@ $(V4_ROM_C) $(V4_MAP_C) &: FORCE
 # the same description as the ROM and v4_map_image (v4/tests/host_map.h), and
 # the ROM assembles it from this kernel's capsule directory: it is made
 # again before the directory is packed, so the three always agree.
-$(CAPSULES_DIR)/v4/sys/map-64.f18 $(CAPSULES_DIR)/v4/sys/map-32.f18: FORCE
+# One rule making both (&:, a grouped target, GNU make 4.3+): with two plain targets make ran the
+# recipe once for each, and under -j the two sub-makes built and ran the same v4/build/mkmap-<w>
+# at once -- "Text file busy", "Permission denied" (#185).
+$(CAPSULES_DIR)/v4/sys/map-64.f18 $(CAPSULES_DIR)/v4/sys/map-32.f18 &: FORCE
 	@$(MAKE) --no-print-directory -C v4 CC=cc sysmap
 
 $(LOADER_OBJ_DIR)/v4engine/v4_rom.o: $(V4_ROM_C) | $(LOADER_OBJ_DIR)
diff --git a/logs/20261112-152711/race-185/after-runs.log b/logs/20261112-152711/race-185/after-runs.log
new file mode 100644
index 00000000..3047c3ac
--- /dev/null
+++ b/logs/20261112-152711/race-185/after-runs.log
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:a6a9c7dba6b783c29be8a1e62feeb9a7faf3bf6401ebc0419f4497238f370845
+size 27483
diff --git a/logs/20261112-152711/race-185/before-runs.log b/logs/20261112-152711/race-185/before-runs.log
new file mode 100644
index 00000000..3b0e2801
--- /dev/null
+++ b/logs/20261112-152711/race-185/before-runs.log
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c546dd08fa4b42be3f7303f1520035763e363ce44187e77e1730c9dc1387e791
+size 55126