diff --git a/toolkit/mozapps/installer/packager.mk b/toolkit/mozapps/installer/packager.mk
index 44004d8c15e0..fd343607aa2c 100644
--- a/toolkit/mozapps/installer/packager.mk
+++ b/toolkit/mozapps/installer/packager.mk
@@ -204,7 +204,7 @@ upload: checksum
 source-package:
 	@echo 'Packaging source tarball...'
 	$(MKDIR) -p $(DIST)/$(PKG_SRCPACK_PATH)
-	(cd $(MOZ_PKG_SRCDIR) && $(CREATE_SOURCE_TAR) - $(DIR_TO_BE_PACKAGED)) | xz -9e > $(SOURCE_TAR)
+	(cd $(MOZ_PKG_SRCDIR) && $(CREATE_SOURCE_TAR) - ./ ) | xz -9e > $(SOURCE_TAR)
 
 hg-bundle:
 	$(MKDIR) -p $(DIST)/$(PKG_SRCPACK_PATH)
diff --git a/toolkit/mozapps/installer/upload-files.mk b/toolkit/mozapps/installer/upload-files.mk
index 8a6cd7a76319..96913dfc5d47 100644
--- a/toolkit/mozapps/installer/upload-files.mk
+++ b/toolkit/mozapps/installer/upload-files.mk
@@ -775,7 +775,7 @@ ifndef MOZ_PKG_SRCDIR
 MOZ_PKG_SRCDIR = $(topsrcdir)
 endif
 
-DIR_TO_BE_PACKAGED ?= ../$(notdir $(topsrcdir))
+SRC_TAR_PREFIX = $(MOZ_APP_NAME)-$(MOZ_PKG_VERSION)
 SRC_TAR_EXCLUDE_PATHS += \
   --exclude='.hg*' \
   --exclude='CVS' \
@@ -788,7 +788,7 @@ ifdef MOZ_OBJDIR
 SRC_TAR_EXCLUDE_PATHS += --exclude='$(MOZ_OBJDIR)'
 endif
 CREATE_SOURCE_TAR = $(TAR) -c --owner=0 --group=0 --numeric-owner \
-  --mode=go-w $(SRC_TAR_EXCLUDE_PATHS) -f
+  --mode=go-w $(SRC_TAR_EXCLUDE_PATHS) --transform='s,^\./,$(SRC_TAR_PREFIX)/,' -f
 
 SOURCE_TAR = $(DIST)/$(PKG_SRCPACK_PATH)$(PKG_SRCPACK_BASENAME).tar.xz
 HG_BUNDLE_FILE = $(DIST)/$(PKG_SRCPACK_PATH)$(PKG_BUNDLE_BASENAME).bundle