diff --git a/patch/prebuild_eudev/rules.d/50-udev-default.rules b/patch/prebuild_eudev/rules.d/50-udev-default.rules
index f7815fa7c1ebf6a0adc3ad71e36c4c2402d72a39..3f3076631c63f04585be3f51321dbc6c271f5819 100644
--- a/patch/prebuild_eudev/rules.d/50-udev-default.rules
+++ b/patch/prebuild_eudev/rules.d/50-udev-default.rules
@@ -88,4 +88,7 @@ KERNEL=="udmabuf", GROUP="kvm"
 
 SUBSYSTEM=="ptp", ATTR{clock_name}=="KVM virtual PTP", SYMLINK += "ptp_kvm"
 
+# When plug-in MEIG modem, add read and write permissions for riladapter_host.
+SUBSYSTEM=="tty", KERNEL=="ttyUSB[0-4]*", GROUP="tty", MODE="0666"
+
 LABEL="default_end"