diff --git a/device.mk b/device.mk
index 4088392..d499b17 100644
--- a/device.mk
+++ b/device.mk
@@ -44,6 +44,18 @@
 PRODUCT_BRAND := Fairphone
 PRODUCT_MANUFACTURER := Fairphone
 
+# Define the build number based on the product flavour and on the build manifest
+# revision
+ifneq (,$(strip $(PRODUCT_FLAVOR)))
+  _BUILD_MANIFEST_REV := $(shell (git -C $(TOPDIR).repo/manifests rev-parse --short=8 HEAD))
+  BUILD_NUMBER := $(PRODUCT_FLAVOR)-$(_BUILD_MANIFEST_REV)
+  HAS_BUILD_NUMBER := true
+else
+  $(error PRODUCT_FLAVOR must be defined)
+endif
+$(warning Build defined as $(BUILD_ID) ($(BUILD_NUMBER)))
+
+
 PRODUCT_PROPERTY_OVERRIDES += ro.frp.pst=/dev/block/bootdevice/by-name/pad
 
 DEVICE_PACKAGE_OVERLAYS += device/fairphone/fp2-common/overlay