Please see the end of life policy and the end of life notices here. The corresponding software is no longer developed nor actively maintained.
Last software is NBSW 3.3.2.5430.
Successor of NB1310 is NB1601.
NB2210, NB2240, NB2241, NB2340, NB2341, NB2500, NB25411), NB2600 and NB2600R share the same processor and hence the same software image. The so far last version is NBSW 3.5.0.108.
Obviously, these products have worked well for many years now. If you face sudden big problems, we recommend:
In the Web Manager enable and configure the connection supervision. In most cases this helps bringing the router online automatically after an incident.
Serve the unzipped image on a TFTP server e.g. TFTPD32. Disable Windows Firewall. In the Web Manager of the router trigger the update like <serverIP>/<folder>
With active Internet connection, in the root console type:
wget https://share.netmodule.com/router/firmware/option/create-data-partition.sh sh create-data-partition.sh reboot wget https://share.netmodule.com/router/firmware/option/update-legacy.sh sh update-legacy.sh
Last but not least think about upgrading to a new product, maybe also from 3G to 4G. Successor of these products is NB2700.