diff --git a/build/targets.all.mak b/build/targets.all.mak
new file mode 100644
index 000000000..989c4fb7b
--- /dev/null
+++ b/build/targets.all.mak
@@ -0,0 +1,60 @@
+ANDROID_GRADLE_KEYSTORE ?= ~/.gradle/google-play-upload.keystore
+ANDROID_GRADLE_PROPERTIES ?= ~/.gradle/gradle.properties
+IOS_MOBILE_PROVISION ?= build/artifacts/NumWorks_Graphing_Calculator_Distribution.mobileprovision
+EMCC ?= emcc
+
+define source_emsdk
+source ~/emsdk/emsdk_env.sh > /dev/null
+endef
+
+define file_check
+@ if test ! -f $(1); \
+  then \
+  echo "Missing file: $(1)"; \
+  exit 1; \
+fi
+endef
+
+define command_check
+@ if ! command -v $(1) > /dev/null; \
+  then \
+  echo "Missing command: $(1), did you forget to source?"; \
+  exit 1; \
+fi
+endef
+
+.PHONY: all_official
+all_official:
+	$(call file_check,$(ANDROID_GRADLE_KEYSTORE))
+	$(call file_check,$(ANDROID_GRADLE_PROPERTIES))
+	$(call file_check,$(IOS_MOBILE_PROVISION))
+	$(call command_check,$(EMCC))
+	$(Q) rm -rf output/stable_release
+	$(Q) mkdir -p output/stable_release
+	$(Q) echo "BUILD_FIRMWARE    DEVICE N0110"
+	$(Q) $(MAKE) clean
+	$(Q) $(MAKE) epsilon.official.onboarding.dfu
+	$(Q) cp output/release/device/n0110/epsilon.official.onboarding.dfu output/stable_release/epsilon.device.n0110.dfu
+	$(Q) echo "BUILD_FIRMWARE    DEVICE N0100"
+	$(Q) $(MAKE) MODEL=n0100 clean
+	$(Q) $(MAKE) MODEL=n0100 epsilon.official.onboarding.dfu
+	$(Q) cp output/release/device/n0100/epsilon.official.onboarding.dfu output/stable_release/epsilon.device.n0100.dfu
+	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB ZIP"
+	$(Q) $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web clean
+	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web output/release/simulator/web/simulator.official.zip
+	$(Q) cp output/release/simulator/web/simulator.official.zip output/stable_release/simulator.web.zip
+	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB JS"
+	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web epsilon.official.js
+	$(Q) cp output/release/simulator/web/epsilon.official.js output/stable_release/epsilon.js
+	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB PYTHON JS"
+	$(Q) $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web clean
+	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web EPSILON_GETOPT=1 EPSILON_APPS=code epsilon.official.js
+	$(Q) cp output/release/simulator/web/epsilon.official.js output/stable_release/epsilon.python.js
+	$(Q) echo "BUILD_FIRMWARE    SIMULATOR ANDROID"
+	$(Q) $(MAKE) PLATFORM=simulator TARGET=android clean
+	$(Q) $(MAKE) PLATFORM=simulator TARGET=android epsilon.official.apk
+	$(Q) cp output/release/simulator/android/app/outputs/apk/release/android-release-unsigned.apk output/stable_release/epsilon.apk
+	$(Q) echo "BUILD_FIRMWARE    SIMULATOR IOS"
+	$(Q) $(MAKE) PLATFORM=simulator TARGET=ios clean
+	$(Q) $(MAKE) PLATFORM=simulator TARGET=ios IOS_PROVISIONNING_PROFILE="~/Downloads/NumWorks_Graphing_Calculator_Distribution.mobileprovision" output/release/simulator/ios/app/epsilon.official.ipa
+	$(Q) cp output/release/simulator/ios/app/epsilon.official.ipa output/stable_release/epsilon.ipa
diff --git a/build/targets.mak b/build/targets.mak
index 4f28bd056..ca7b9d97c 100644
--- a/build/targets.mak
+++ b/build/targets.mak
@@ -36,55 +36,4 @@ endef
 
 $(foreach extension,$(HANDY_TARGETS_EXTENSIONS),$(foreach executable,$(HANDY_TARGETS),$(eval $(call handy_target_rule,$(executable),$(extension)))))
 
-define source_emsdk
-source ~/emsdk/emsdk_env.sh > /dev/null
-endef
-
-ANDROID_GRADLE_KEYSTORE:= $(wildcard ~/.gradle/google-play-upload.keystore)
-ANDROID_GRADLE_PROPERTIES:= $(wildcard ~/.gradle/gradle.properties)
-IOS_MOBILE_PROVISION:= $(wildcard ~/Downloads/NumWorks_Graphing_Calculator_Distribution.mobileprovision)
-
-MISSING_FILES=1
-
-ifneq "$(and $(ANDROID_GRADLE_KEYSTORE),$(ANDROID_GRADLE_PROPERTIES))" ""
-ifneq "$(IOS_MOBILE_PROVISION)" ""
-  MISSING_FILES=0
-endif
-endif
-
-.PHONY: stable_release
-ifeq ($(MISSING_FILES),1)
-stable_release:
-	@echo "Some required files for app signing are missing among: ~/.gradle/google-play-upload.keystore, ~/.gradle/gradle.properties or ~/Downloads/NumWorks_Graphing_Calculator_Distribution.mobileprovision."
-else
-stable_release:
-	$(Q) rm -rf output/stable_release
-	$(Q) mkdir -p output/stable_release
-	$(Q) echo "BUILD_FIRMWARE    DEVICE N0110"
-	$(Q) $(MAKE) clean
-	$(Q) $(MAKE) epsilon.official.onboarding.dfu
-	$(Q) cp output/release/device/n0110/epsilon.official.onboarding.dfu output/stable_release/epsilon.device.n0110.dfu
-	$(Q) echo "BUILD_FIRMWARE    DEVICE N0100"
-	$(Q) $(MAKE) MODEL=n0100 clean
-	$(Q) $(MAKE) MODEL=n0100 epsilon.official.onboarding.dfu
-	$(Q) cp output/release/device/n0100/epsilon.official.onboarding.dfu output/stable_release/epsilon.device.n0100.dfu
-	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB ZIP"
-	$(Q) $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web clean
-	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web output/release/simulator/web/simulator.official.zip
-	$(Q) cp output/release/simulator/web/simulator.official.zip output/stable_release/simulator.web.zip
-	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB JS"
-	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web epsilon.official.js
-	$(Q) cp output/release/simulator/web/epsilon.official.js output/stable_release/epsilon.js
-	$(Q) echo "BUILD_FIRMWARE    SIMULATOR WEB PYTHON JS"
-	$(Q) $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web clean
-	$(Q) $(call source_emsdk); $(MAKE) DEBUG=0 PLATFORM=simulator TARGET=web EPSILON_GETOPT=1 EPSILON_APPS=code epsilon.official.js
-	$(Q) cp output/release/simulator/web/epsilon.official.js output/stable_release/epsilon.python.js
-	$(Q) echo "BUILD_FIRMWARE    SIMULATOR ANDROID"
-	$(Q) $(MAKE) PLATFORM=simulator TARGET=android clean
-	$(Q) $(MAKE) PLATFORM=simulator TARGET=android epsilon.official.apk
-	$(Q) cp output/release/simulator/android/app/outputs/apk/release/android-release-unsigned.apk output/stable_release/epsilon.apk
-	$(Q) echo "BUILD_FIRMWARE    SIMULATOR IOS"
-	$(Q) $(MAKE) PLATFORM=simulator TARGET=ios clean
-	$(Q) $(MAKE) PLATFORM=simulator TARGET=ios IOS_PROVISIONNING_PROFILE="~/Downloads/NumWorks_Graphing_Calculator_Distribution.mobileprovision" output/release/simulator/ios/app/epsilon.official.ipa
-	$(Q) cp output/release/simulator/ios/app/epsilon.official.ipa output/stable_release/epsilon.ipa
-endif
+include build/targets.all.mak