sim card not recognized and firmware update failed

sim card not recognized and firmware update failed

sim card not recognized and firmware update failed
sim card not recognized and firmware update failed
2026-04-01 14:25:21 - last edited Yesterday
Model: TL-MR6400  
Hardware Version: V4
Firmware Version: 1.16 .0 0.9.1 v0001.0 Build 191223 Rel.66638n
Hello

I have a 4G router model TL-MR6400 V4 that does not recognize any kind of SIM card...I tend to think that the problem is with the older firmware version 1.12

I tried to upgrade to version 1.16 .0 0.9.1 v0001.0 Build 191223 Rel.66638n but when I access the _update_ button I get the message download failed
I mention that the router works fine in wireless mode and I have access to the internet
What can I do
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#1
1 Accepted Solution
Re:sim card not recognized and firmware update failed-Solution
2026-04-02 07:57:07 - last edited Yesterday

Hello @moisa ,

Welcome to our community.

 

For the SIM Card Recognition, please follow these troubleshooting steps:
1. Reinsert the SIM card, making sure it is inserted correctly and firmly: How do I install a SIM card for my 4G Wi-Fi router or Mobile Wi-Fi?
2. Restart the router while the SIM card is still inserted, then check the SIM card status on the Advanced > Status page by logging into http://tplinkmodem.net
3. Test the SIM card on another 4G router or smartphone to ensure the SIM card itself is working fine: How can I check if my SIM card is working via phone?
4. If possible, try inserting a different SIM card
5. Try a factory reset by holding the reset button for about 10 seconds until the power LED starts flashing

For more details: What should I do if my TP-Link 4G LTE Router cannot detect SIM card?

 

For the Firmware Upgrade Failure,please try these steps:
   • Change the router's DNS settings: Go to http://tplinkmodem.net, navigate to Advanced > Network > Internet, and change the DNS servers to 8.8.8.8 and 1.1.1.1
   • Reboot the router and attempt the upgrade again

 

For more detailed troubleshooting: What should I do if fail to upgrade the firmware of my TP-Link router?

Welcome to Community! Get the latest posts: △New Firmware for Archer GE550/GE650 V1 Introduces AI-QoS, EasyMesh IoT Expansion, and More! △New Firmware Releases for Archer BE805 V1/BE450 V1 to Support VPN Merge, New ECO Mode, and More! More posts, please see: △ Get the Ongoing Pre-release Firmware for Wi-Fi Routers Here— Subscribe for Updates! Urgent problems with your Wi-Fi Router, Range Extender, or DSL Modem? Please reach out via private Messages or @Joesph-TP in your new thread directly. Click Or ☆Recommended Solution if the post/answer helps.
Recommended Solution
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#2
1 Reply
Re:sim card not recognized and firmware update failed-Solution
2026-04-02 07:57:07 - last edited Yesterday

Hello @moisa ,

Welcome to our community.

 

For the SIM Card Recognition, please follow these troubleshooting steps:
1. Reinsert the SIM card, making sure it is inserted correctly and firmly: How do I install a SIM card for my 4G Wi-Fi router or Mobile Wi-Fi?
2. Restart the router while the SIM card is still inserted, then check the SIM card status on the Advanced > Status page by logging into http://tplinkmodem.net
3. Test the SIM card on another 4G router or smartphone to ensure the SIM card itself is working fine: How can I check if my SIM card is working via phone?
4. If possible, try inserting a different SIM card
5. Try a factory reset by holding the reset button for about 10 seconds until the power LED starts flashing

For more details: What should I do if my TP-Link 4G LTE Router cannot detect SIM card?

 

For the Firmware Upgrade Failure,please try these steps:
   • Change the router's DNS settings: Go to http://tplinkmodem.net, navigate to Advanced > Network > Internet, and change the DNS servers to 8.8.8.8 and 1.1.1.1
   • Reboot the router and attempt the upgrade again

 

For more detailed troubleshooting: What should I do if fail to upgrade the firmware of my TP-Link router?

Welcome to Community! Get the latest posts: △New Firmware for Archer GE550/GE650 V1 Introduces AI-QoS, EasyMesh IoT Expansion, and More! △New Firmware Releases for Archer BE805 V1/BE450 V1 to Support VPN Merge, New ECO Mode, and More! More posts, please see: △ Get the Ongoing Pre-release Firmware for Wi-Fi Routers Here— Subscribe for Updates! Urgent problems with your Wi-Fi Router, Range Extender, or DSL Modem? Please reach out via private Messages or @Joesph-TP in your new thread directly. Click Or ☆Recommended Solution if the post/answer helps.
Recommended Solution
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#2