diff --git a/adb_test.go b/adb_test.go
index 95f63f2..b94b6ce 100644
--- a/adb_test.go
+++ b/adb_test.go
@@ -59,9 +59,14 @@ func TestNormalizeAddr(t *testing.T) {
 	}{
 		{in: "192.168.1.5", want: "192.168.1.5:5555"},
 		{in: "192.168.1.5:5556", want: "192.168.1.5:5556"},
+		{in: "2001:db8::1", want: "[2001:db8::1]:5555"},
+		{in: "[2001:db8::1]:5556", want: "[2001:db8::1]:5556"},
 		{in: "mydevice.local", want: "mydevice.local:5555"},
 		{in: "phone:5555", want: "phone:5555"},
 		{in: "", wantErr: true},
+		{in: "phone:", wantErr: true},
+		{in: "phone:not-a-port", wantErr: true},
+		{in: "phone:70000", wantErr: true},
 	}
 	for _, tt := range tests {
 		got, err := normalizeAddr(tt.in)
diff --git a/device.go b/device.go
index 587c312..f417b22 100644
--- a/device.go
+++ b/device.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"strconv"
 	"strings"
 )
 
@@ -221,7 +222,13 @@ func normalizeAddr(addr string) (string, error) {
 		if host == "" || port == "" {
 			return "", fmt.Errorf("invalid device address %q", addr)
 		}
+		if _, err := strconv.ParseUint(port, 10, 16); err != nil {
+			return "", fmt.Errorf("invalid device address %q", addr)
+		}
 		return addr, nil
 	}
+	if strings.Contains(addr, ":") {
+		return "", fmt.Errorf("invalid device address %q", addr)
+	}
 	return net.JoinHostPort(addr, "5555"), nil
 }