diff --git a/make/py-defs.mk b/make/py-defs.mk
index adf3c2c3..98c22bbb 100644
--- a/make/py-defs.mk
+++ b/make/py-defs.mk
@@ -3,14 +3,14 @@ include $(JWBDIR)/make/py-version.mk
 PY_INSTALL_INIT_PY          ?= true
 PY_UPDATE_INIT_PY           ?= true
 PY_INSTALL                  ?= true
-PY_INSTALL_REG              ?= true
+PY_DO_INSTALL_REG           ?= true
 
 ifneq ($(PY_INSTALL),true)
-  PY_INSTALL_REG             = false
+  PY_DO_INSTALL_REG          = false
 endif
-PY_INSTALL_PYC              ?= true
-ifneq ($(PY_INSTALL_REG),true)
-  PY_INSTALL_PYC             = false
+PY_DO_INSTALL_PYC           ?= true
+ifneq ($(PY_DO_INSTALL_REG),true)
+  PY_DO_INSTALL_PYC          = false
 endif
 
 ifeq ($(DEVELOPMENT),true)
@@ -20,13 +20,16 @@ else
 endif
 
 PY_SRC_PY                   ?= $(wildcard *.py)
-PY_ALL_PY                    = $(filter-out __init__.py,$(PY_SRC_PY))
+PY_LOCAL_PY                  = $(PY_SRC_PY)
+PY_INSTALL_PY                = $(filter-out __init__.py,$(PY_SRC_PY))
 
 ifneq ($(PYTHON_MAJOR),3)
-  PY_PYC                     = $(patsubst %.py,%.pyc,$(PY_ALL_PY))
+  PY_LOCAL_PYC               = $(patsubst %.py,%.pyc,$(PY_LOCAL_PY))
+  PY_INSTALL_PYC             = $(patsubst %.py,%.pyc,$(PY_INSTALL_PY))
 else
   PY_CPYTHON_PREFIX         := $(shell $(PYTHON) -c "import sys; print('cpython-{}{}'.format(sys.version_info[0],sys.version_info[1]))")
-  PY_PYC                     = $(patsubst %.py,__pycache__/%.$(PY_CPYTHON_PREFIX).pyc,$(PY_ALL_PY))
+  PY_LOCAL_PYC               = $(patsubst %.py,__pycache__/%.$(PY_CPYTHON_PREFIX).pyc,$(PY_LOCAL_PY))
+  PY_INSTALL_PYC             = $(patsubst %.py,__pycache__/%.$(PY_CPYTHON_PREFIX).pyc,$(PY_INSTALL_PY))
 endif
 
 ifneq ($(PY_INSTALL_DIR),)
@@ -46,7 +49,10 @@ ifeq ($(PY_INSTALL_DIR_PY),)
   endif
   PY_MOD                    ?= $(subst /,.,$(PY_INSTALL_MOD))
   ifeq ($(PY_INSTALL_INIT_PY),true)
-    PY_ALL_PY               += __init__.py
+    PY_INSTALL_PY           += __init__.py
+    PY_LOCAL_PY             += __init__.py
+  else ifeq ($(PY_UPDATE_INIT_PY),true)
+    PY_LOCAL_PY             += __init__.py
   endif
   PY_INSTALL_DIR_PY         ?= $(ENV_PREFIX)$(PY_SITE_PACKAGES_PATH)/$(patsubst .,/,$(PY_INSTALL_MOD))
 else
@@ -62,12 +68,12 @@ else
 endif
 
 PY_INSTALL_DIRS             ?= $(sort $(PY_INSTALL_DIR_PY) $(PY_INSTALL_DIR_PYC))
-PY_INSTALLED_PY              = $(addprefix $(PY_INSTALL_DIR_PY)/,$(sort $(PY_ALL_PY)))
+PY_INSTALLED_PY              = $(addprefix $(PY_INSTALL_DIR_PY)/,$(sort $(PY_INSTALL_PY)))
 PY_INSTALLED_PY_TYPED        = $(addprefix $(PY_INSTALL_DIR_PY)/,$(wildcard py.typed))
-ifeq ($(PY_INSTALL_PYC),true)
-  PY_INSTALLED_PYC           = $(addprefix $(PY_INSTALL_DIR_PY)/,$(PY_PYC))
+ifeq ($(PY_DO_INSTALL_PYC),true)
+  PY_INSTALLED_PYC           = $(addprefix $(PY_INSTALL_DIR_PY)/,$(PY_INSTALL_PYC))
 endif
-ifeq ($(PY_INSTALL_REG),true)
+ifeq ($(PY_DO_INSTALL_REG),true)
   PY_INSTALLED_REG           = $(PY_INSTALLED_PY) $(PY_INSTALLED_PYC) $(PY_INSTALLED_PY_TYPED)
 endif
 
diff --git a/make/py-mod.mk b/make/py-mod.mk
index 54ac1bf6..a660e750 100644
--- a/make/py-mod.mk
+++ b/make/py-mod.mk
@@ -23,7 +23,7 @@ endif
 #leftparen                  := (
 #PY_EXPORT                  ?= $(shell sed '/\(class\|def\) ..*\# *export/ !d; s/\(class\|def\) *//; s/[$(leftparen):].*//' $(PY_SRC_PY))
 
-all: $(PY_PYC)
+all: $(PY_LOCAL_PYC)
 install: install-dirs.done install-reg.done
 clean: invalidate-testability py.clean
 distclean:
@@ -34,6 +34,6 @@ ifeq ($(PY_UPDATE_INIT_PY),true)
 __init__.py: $(PY_INIT_TMPL) $(filter-out __init__.py,$(PY_SRC_PY))
 	if [ "$(PY_INIT_TMPL)" ]; then cat "$(PY_INIT_TMPL)" > $@.tmp; else > $@.tmp; fi
 	set -e -o pipefail; $(PY_GENERATE_INIT_PY) \
-		$(filter-out __init__.py,$(PY_ALL_PY)) $(SUBDIRS_TO_ITERATE) | $(PY_INIT_FILTER) | tee -a $@.tmp
+		$(filter-out __init__.py,$(PY_LOCAL_PY)) $(SUBDIRS_TO_ITERATE) | $(PY_INIT_FILTER) | tee -a $@.tmp
 	mv $@.tmp $@
 endif
diff --git a/make/py-rules.mk b/make/py-rules.mk
index acf463ff..73f098fe 100644
--- a/make/py-rules.mk
+++ b/make/py-rules.mk
@@ -2,8 +2,10 @@ all:
 
 py.clean:
 	$(RM) -f *.done *.pyc *.rep
-	/bin/bash $(JWB_SCRIPT_DIR)/scm.sh clean -f __init__.py
 	$(RM) -rf __pycache__ .mypy_cache
+ifeq ($(PY_UPDATE_INIT_PY),true)
+	/bin/bash $(JWB_SCRIPT_DIR)/scm.sh clean -f __init__.py
+endif
 
 install-dirs.done:
 	$(INSTALL) -d -m $(PYJWBDIRMODE) -o $(PYJWBDIROWNER) -g $(PYJWBDIRGROUP) $(PY_INSTALL_DIRS)