diff --git a/cli/cli.go b/cli/cli.go
index cbfab85eb77..ee32b40a154 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -78,6 +78,7 @@ func createCliCommandTree(cmd *cobra.Command) {
 	cmd.PersistentFlags().BoolVar(&globals.Debug, "debug", false, "Enables debug output (super verbose, used to debug the CLI).")
 	cmd.PersistentFlags().StringVar(&outputFormat, "format", "text", "The output format, can be [text|json].")
 	cmd.PersistentFlags().StringVar(&globals.YAMLConfigFile, "config-file", "", "The custom config file (if not specified the default will be used).")
+	cmd.PersistentFlags().StringSliceVar(&globals.AdditionalUrls, "additional-urls", []string{}, "Additional URLs for the board manager.")
 }
 
 func preRun(cmd *cobra.Command, args []string) {
diff --git a/cli/globals/globals.go b/cli/globals/globals.go
index 556b125b69f..92e831afba3 100644
--- a/cli/globals/globals.go
+++ b/cli/globals/globals.go
@@ -39,6 +39,8 @@ var (
 	Config *configs.Configuration
 	// YAMLConfigFile contains the path to the config file
 	YAMLConfigFile string
+	// AdditionalUrls contains the list of additional urls the boards manager can use
+	AdditionalUrls []string
 )
 
 func getHTTPClientHeader() http.Header {
diff --git a/cli/instance/instance.go b/cli/instance/instance.go
index 76604d4beb8..d7e73eded0e 100644
--- a/cli/instance/instance.go
+++ b/cli/instance/instance.go
@@ -62,6 +62,11 @@ func initInstance() *rpc.InitResp {
 
 func packageManagerInitReq() *rpc.InitReq {
 	urls := []string{}
+
+	for _, urlString := range globals.AdditionalUrls {
+		urls = append(urls, urlString)
+	}
+
 	for _, URL := range globals.Config.BoardManagerAdditionalUrls {
 		urls = append(urls, URL.String())
 	}
diff --git a/test/test_board.py b/test/test_board.py
index 76351e1f4b3..66f3b198f5c 100644
--- a/test/test_board.py
+++ b/test/test_board.py
@@ -19,7 +19,7 @@
 
 
 @pytest.mark.skipif(running_on_ci(), reason="VMs have no serial ports")
-def test_board_list(run_command):
+def test_core_list(run_command):
     result = run_command("core update-index")
     assert result.ok
     result = run_command("board list --format json")
@@ -33,9 +33,29 @@ def test_board_list(run_command):
 
 
 @pytest.mark.skipif(running_on_ci(), reason="VMs have no serial ports")
-def test_board_listall(run_command):
+def test_core_listall(run_command):
     assert run_command("core update-index")
     result = run_command("board listall")
     print(result.stderr, result.stdout)
     assert result.ok
     assert ["Board", "Name", "FQBN"] == result.stdout.splitlines()[0].strip().split()
+
+
+def test_core_search(run_command):
+    url = "https://raw.githubusercontent.com/arduino/arduino-cli/master/test/testdata/test_index.json"
+    assert run_command("core update-index --additional-urls={}".format(url))
+    # default search
+    result = run_command("core search avr")
+    assert result.ok
+    assert 2 < len(result.stdout.splitlines())
+    result = run_command("core search avr --format json")
+    assert result.ok
+    data = json.loads(result.stdout)
+    assert 0 < len(data)
+    # additional URL
+    result = run_command(
+        "core search test_core --format json --additional-urls={}".format(url)
+    )
+    assert result.ok
+    data = json.loads(result.stdout)
+    assert 1 == len(data)
diff --git a/test/testdata/core.txt b/test/testdata/core.txt
new file mode 100644
index 00000000000..72c5593cdcb
--- /dev/null
+++ b/test/testdata/core.txt
@@ -0,0 +1 @@
+HELO
diff --git a/test/testdata/test_index.json b/test/testdata/test_index.json
new file mode 100644
index 00000000000..d84277fbc13
--- /dev/null
+++ b/test/testdata/test_index.json
@@ -0,0 +1,35 @@
+{
+    "packages": [
+        {
+            "maintainer": "Arduino",
+            "help": {
+                "online": "https://github.com/Arduino/arduino-cli"
+            },
+            "websiteURL": "https://github.com/Arduino/arduino-cli",
+            "platforms": [
+                {
+                    "category": "Test Category",
+                    "help": {
+                        "online": "https://github.com/Arduino/arduino-cli"
+                    },
+                    "url": "https://raw.githubusercontent.com/arduino/arduino-cli/massi/additional-urls/test/testdata/core.txt",
+                    "checksum": "SHA-256:1ba93f6aea56842dfef065c0f5eb0a34c1f78b72b3f2426c94e47ba3a359c9ff",
+                    "name": "test_core",
+                    "version": "1.0.0",
+                    "architecture": "x86",
+                    "archiveFileName": "core.txt",
+                    "size": "2799",
+                    "toolsDependencies": [],
+                    "boards": [
+                        {
+                            "name": "Test Board"
+                        }
+                    ]
+                }
+            ],
+            "tools": [],
+            "email": "test@example.com",
+            "name": "test"
+        }
+    ]
+}