diff --git a/builtin/am.c b/builtin/am.c
index 4b89289d1e..e39142e4d2 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2148,7 +2148,7 @@ static void am_abort(struct am_state *state)
 	am_rerere_clear();
 
 	curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
-	has_curr_head = !is_null_oid(&curr_head);
+	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
 		hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
 
diff --git a/builtin/checkout.c b/builtin/checkout.c
index e079a7dc83..b360943455 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -835,7 +835,8 @@ static int switch_branches(const struct checkout_opts *opts,
 	int flag, writeout_error = 0;
 	memset(&old, 0, sizeof(old));
 	old.path = path_to_free = resolve_refdup("HEAD", 0, rev.hash, &flag);
-	old.commit = lookup_commit_reference_gently(rev.hash, 1);
+	if (old.path)
+		old.commit = lookup_commit_reference_gently(rev.hash, 1);
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;