diff --git a/build/jam/FileRules b/build/jam/FileRules
index ec309c4733..22b9eb004e 100644
--- a/build/jam/FileRules
+++ b/build/jam/FileRules
@@ -373,7 +373,7 @@ rule DetermineHaikuRevision
 	# root directory, so it gets updated when the revision changes due to
 	# commits or merges.
 	local gitIndex = <haiku-rootdir-git>index ;
-	local revisionFile = <haiku-rootdir-git>haiku-revision ;
+	local revisionFile = <haiku-rootdir>haiku-revision ;
 	if ! [ on $(gitIndex) return $(HAIKU_GIT_REVISION_DETERMINED) ] {
 		HAIKU_GIT_REVISION_DETERMINED on $(gitIndex) = 1 ;
 		MakeLocate $(revisionFile) : $(HAIKU_BUILD_OUTPUT_DIR) ;
@@ -424,6 +424,12 @@ rule DetermineEffectiveHaikuRevision
 actions DetermineEffectiveHaikuRevision1
 {
 	revision=`sed -n 's,^\(hrev[0-9]*\).*,\1,p' "$(2:E=unknown-revision)"`
+	if [ -z "$revision" ]; then
+		echo "Error: unable to determine the effective Haiku revision."
+		echo "       If you are using a Haiku clone without tags, you can set"
+		echo "       the revision tag to use with e.g. HAIKU_REVISION=hrev43210"
+		exit 1
+	fi
 	echo "${revision:-0}" > "$(1)"
 }
 
diff --git a/build/scripts/determine_haiku_revision b/build/scripts/determine_haiku_revision
index 465180a12e..0796c8c2e0 100755
--- a/build/scripts/determine_haiku_revision
+++ b/build/scripts/determine_haiku_revision
@@ -31,8 +31,10 @@ if [ -z "$revision" -o "$lastBuiltRevision" != "$localRev" ]; then
 	# last reachable hrev-(haiku-revision-)tag
 	revision=`git describe --dirty --tags --match=hrev*`
 	if [ -z "$revision" ]; then
-		# failed to find any hrev tags, use short hash instead
-		revision=`git rev-parse --short HEAD`
+		# failed to find any hrev tags, bail out
+		echo "Error: you are using a Haiku clone without tags, please set"
+		echo "       the revision tag to use (e.g. HAIKU_REVISION=hrev43210)"
+		exit 1
 	elif echo "$revision" | grep -- '-' >/dev/null; then
 		# HEAD is not directly a changeset from Haiku's central repo, so we
 		# add the current branch name as additional info