diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 00ffb36394..949bfa796b 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -224,7 +224,8 @@ static int cmd_multi_pack_index_write(int argc, const char **argv,
 	}
 
 	ret = write_midx_file(source, opts.preferred_pack,
-			      opts.refs_snapshot, opts.flags);
+			      opts.refs_snapshot, opts.incremental_base,
+			      opts.flags);
 
 	free(opts.refs_snapshot);
 	return ret;
diff --git a/builtin/repack.c b/builtin/repack.c
index 1524a9c13a..0092a72a99 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -629,7 +629,7 @@ int cmd_repack(int argc,
 		unsigned flags = 0;
 		if (git_env_bool(GIT_TEST_MULTI_PACK_INDEX_WRITE_INCREMENTAL, 0))
 			flags |= MIDX_WRITE_INCREMENTAL;
-		write_midx_file(existing.source, NULL, NULL, flags);
+		write_midx_file(existing.source, NULL, NULL, NULL, flags);
 	}
 
 cleanup:
diff --git a/midx-write.c b/midx-write.c
index 561e9eedc0..aa438775eb 100644
--- a/midx-write.c
+++ b/midx-write.c
@@ -1850,12 +1850,14 @@ cleanup:
 int write_midx_file(struct odb_source *source,
 		    const char *preferred_pack_name,
 		    const char *refs_snapshot,
+		    const char *incremental_base,
 		    unsigned flags)
 {
 	struct write_midx_opts opts = {
 		.source = source,
 		.preferred_pack_name = preferred_pack_name,
 		.refs_snapshot = refs_snapshot,
+		.incremental_base = incremental_base,
 		.flags = flags,
 	};
 
diff --git a/midx.h b/midx.h
index 63853a03a4..92ed29d913 100644
--- a/midx.h
+++ b/midx.h
@@ -131,7 +131,7 @@ int prepare_multi_pack_index_one(struct odb_source *source);
  */
 int write_midx_file(struct odb_source *source,
 		    const char *preferred_pack_name, const char *refs_snapshot,
-		    unsigned flags);
+		    const char *incremental_base, unsigned flags);
 int write_midx_file_only(struct odb_source *source,
 			 struct string_list *packs_to_include,
 			 const char *preferred_pack_name,
diff --git a/t/t5334-incremental-multi-pack-index.sh b/t/t5334-incremental-multi-pack-index.sh
index 68a103d13d..69e96bf8d9 100755
--- a/t/t5334-incremental-multi-pack-index.sh
+++ b/t/t5334-incremental-multi-pack-index.sh
@@ -119,7 +119,7 @@ test_expect_success 'write MIDX layer with --base without --no-write-chain-file'
 	test_grep "cannot use --base without --no-write-chain-file" err
 '
 
-test_expect_success 'write MIDX layer with --base=none and --no-write-chain-file' '
+test_expect_failure 'write MIDX layer with --base=none and --no-write-chain-file' '
 	test_commit base-none &&
 	git repack -d &&
 
@@ -128,19 +128,33 @@ test_expect_success 'write MIDX layer with --base=none and --no-write-chain-file
 		--no-write-chain-file --base=none)" &&
 
 	test_cmp "$midx_chain.bak" "$midx_chain" &&
-	test_path_is_file "$midxdir/multi-pack-index-$layer.midx"
+	test_path_is_file "$midxdir/multi-pack-index-$layer.midx" &&
+
+	echo "$layer" >"$midx_chain" &&
+	test-tool read-midx --show-objects "$objdir" "$layer" >midx.objects &&
+	test_grep "^$(git rev-parse 2.2) " midx.objects &&
+	cp "$midx_chain.bak" "$midx_chain"
 '
 
-test_expect_success 'write MIDX layer with --base=<hash> and --no-write-chain-file' '
+test_expect_failure 'write MIDX layer with --base=<hash> and --no-write-chain-file' '
 	test_commit base-hash &&
 	git repack -d &&
 
 	cp "$midx_chain" "$midx_chain.bak" &&
+	base="$(nth_line 1 "$midx_chain")" &&
 	layer="$(git multi-pack-index write --bitmap --incremental \
-		--no-write-chain-file --base="$(nth_line 1 "$midx_chain")")" &&
+		--no-write-chain-file --base="$base")" &&
 
 	test_cmp "$midx_chain.bak" "$midx_chain" &&
-	test_path_is_file "$midxdir/multi-pack-index-$layer.midx"
+	test_path_is_file "$midxdir/multi-pack-index-$layer.midx" &&
+
+	{
+		echo "$base" &&
+		echo "$layer"
+	} >"$midx_chain" &&
+	test-tool read-midx --show-objects "$objdir" "$layer" >midx.objects &&
+	test_grep "^$(git rev-parse 2.2) " midx.objects &&
+	cp "$midx_chain.bak" "$midx_chain"
 '
 
 for reuse in false single multi