diff --git a/docs/guides/build-circuitpython-firmware-with-lvgl.md b/docs/guides/build-circuitpython-firmware-with-lvgl.md
index ec46f6e..c8e2bdd 100644
--- a/docs/guides/build-circuitpython-firmware-with-lvgl.md
+++ b/docs/guides/build-circuitpython-firmware-with-lvgl.md
@@ -73,20 +73,21 @@ them. For a worked example with a partition table, see
 `USER_C_MODULES`:
 
 ```bash
-./build_mp.py --interpreter circuitpython --port unix \
-    --modules /path/to/omnipython-lvgl/ports/circuitpython,pygraphics
+./build_mp.py --interpreter circuitpython --port unix --modules lvgl,pygraphics
 ```
 
-`--modules` takes a short name for each module that lives in
-micropython-pydevices and a full path for one that doesn't, such as this
-port. The binary lands in `builds/circuitpython/unix/coverage/`.
+`lvgl` is this port: `build_mp.py` fetches omnipython-lvgl at the commit its
+`modules.lock` pins, or uses an `omnipython-lvgl` checkout beside it. To build
+another checkout, name its port by path instead
+(`--modules /path/to/omnipython-lvgl/ports/circuitpython,pygraphics`). The
+binary lands in `builds/circuitpython/unix/coverage/`.
 
 For a board, name CircuitPython's port and board, and put `CIRCUITPY_GIFIO=0`
 at the end:
 
 ```bash
 ./build_mp.py --interpreter circuitpython --port espressif \
-    --board <board> --modules /path/to/omnipython-lvgl/ports/circuitpython CIRCUITPY_GIFIO=0
+    --board <board> --modules lvgl CIRCUITPY_GIFIO=0
 ```
 
 ## Check the build
diff --git a/docs/guides/build-micropython-firmware-with-lvgl.md b/docs/guides/build-micropython-firmware-with-lvgl.md
index 1c02f5d..860f2d9 100644
--- a/docs/guides/build-micropython-firmware-with-lvgl.md
+++ b/docs/guides/build-micropython-firmware-with-lvgl.md
@@ -66,6 +66,15 @@ several such files builds them all.
 `build_mp.py` does that for you: name the modules and it builds them on a
 port, with upstream's own boards.
 
+```bash
+./build_mp.py --port unix --modules lvgl,pygraphics
+```
+
+`lvgl` is this port: `build_mp.py` fetches omnipython-lvgl at the commit its
+`modules.lock` pins, or uses an `omnipython-lvgl` checkout beside it. To build
+another checkout, name its port by path instead
+(`--modules /path/to/omnipython-lvgl/ports/micropython,pygraphics`).
+
 Add `jpegio` when you want JPEG images:
 [Show JPEG images](show-jpeg-images.md) says why.
 
diff --git a/docs/guides/show-jpeg-images.md b/docs/guides/show-jpeg-images.md
index 2dbf6f0..63099db 100644
--- a/docs/guides/show-jpeg-images.md
+++ b/docs/guides/show-jpeg-images.md
@@ -36,7 +36,7 @@ Name jpegio when you build with
 [micropython-pydevices](https://github.com/PyDevices/micropython-pydevices):
 
 ```bash
-./build_mp.py --port unix --variant pydevices --modules jpegio,lvgl-micropython
+./build_mp.py --port unix --variant pydevices --modules jpegio,lvgl
 ```
 
 On a build that has both, `jpegio.register_lvgl_decoder()` and
diff --git a/ports/micropython/micropython.mk b/ports/micropython/micropython.mk
index ea93ff9..d8b8894 100644
--- a/ports/micropython/micropython.mk
+++ b/ports/micropython/micropython.mk
@@ -88,8 +88,11 @@ USERMOD_DIRS += $(BINDINGS_DIR)
 # py.mk sorts the module directories and strips the first that matches, so
 # the root (a prefix of this directory) names every object here, this
 # module's own src/ included. A MicroPython that strips only this directory
-# names src/ by it, hence the second spelling.
-LVMP_OBJ = $(BUILD)/$(patsubst $(BINDINGS_DIR)/%,$(notdir $(BINDINGS_DIR))/%,$(1)) $(BUILD)/$(patsubst $(LVMP_DIR)/%,$(notdir $(LVMP_DIR))/%,$(1)) $(if $(findstring :,$(1)),,$(BUILD)/$(1))
+# names src/ by it, hence the second spelling. A spelling a pattern didn't
+# match is still the absolute path, so every spelling whose part under
+# $(BUILD) holds a colon is dropped, not only the third. $(BUILD) itself may
+# hold a drive colon (an absolute build directory on Windows); that is fine.
+LVMP_OBJ = $(addprefix $(BUILD)/,$(foreach o,$(patsubst $(BINDINGS_DIR)/%,$(notdir $(BINDINGS_DIR))/%,$(1)) $(patsubst $(LVMP_DIR)/%,$(notdir $(LVMP_DIR))/%,$(1)) $(1),$(if $(findstring :,$(o)),,$(o))))
 $(foreach s,$(SOURCES),\
 	$(eval $(call LVMP_OBJ,$(s:.c=.o)): CFLAGS += $(LVMP_FLOAT_CFLAGS)))
 $(eval $(call LVMP_OBJ,$(LVMP_C:.c=.o)): CFLAGS += $(LVMP_FLOAT_CFLAGS))