From 31062d82c560918bd74b676b5eaf5b9f8bf395e3 Mon Sep 17 00:00:00 2001
From: GNU <dexterkidd@gmail.com>
Date: Sat, 9 Sep 2023 12:30:30 +0800
Subject: [PATCH] Updated How to upgrade 4G extension firmware (markdown)

---
 How-to-upgrade-4G-extension-firmware.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/How-to-upgrade-4G-extension-firmware.md b/How-to-upgrade-4G-extension-firmware.md
index c0d4a43..6bf7d30 100644
--- a/How-to-upgrade-4G-extension-firmware.md
+++ b/How-to-upgrade-4G-extension-firmware.md
@@ -196,6 +196,14 @@ https://techship.com/faq/how-to-automated-connection-establishment-with-sim7600-
 
 # Useful AT commands
 
+* check firmware version
+```
+echo -en "AT+GMR\r\n" | sudo socat - /dev/ttyUSB2,crnl
++GMR: LE20B04SIM7600G22
+OK
+
+```
+
 * check sim card status
 ```
 echo -en  "AT+cpin?\r\n" |sudo socat - /dev/ttyUSB2,crnl