You can update the firmware of your GSM5212 via its web-GUI. Here are the steps:
1. Download the latest firmware for the GSM5212 which is v10.0.2.35 here.
2. Connect the PC where you have downloaded the firmware v10.0.2.35 to a LAN port on your GSM5212. Make sure to unzip the firmware.
3. Login to the web-GUI of your GSM5212.
Note: If there is a Management VLAN configured on your GSM5212 then be sure that your PC is connected to the port that belongs to the Management VLAN and set the corresponding static IP Address to your PC so that you can access the web-GUI.
4. Once your logged-in to the web-GUI, go to Maintenance > Download > HTTP File Download.
5. On File Type, select Archive. On Image Name, select image1.
6. Click Browse then locate the firmware v10.0.2.35 that you have unzipped earlier.
7. Click Apply.
Note: After a file transfer is started, please wait until the page refreshes. When the page refreshes, the Select File option will be blanked out. This indicates that the upgrade process is done.
If you need assistance, you can open a support ticket with NETGEAR Support here at anytime and one of the NETEGAR Support Experts will walk you through in updating the firmware of your GSM5212.
