Using an example, I will update the firmware of the D-Link DES-3528 switch.
To get started, download the latest firmware from the official forum
http://forum.dlink.ru/viewtopic.php?f=2&t=92700
Unpack the downloaded archive and transfer the firmware files to the tftp server. How to start and configure a tftp server can be found in my articles:
Starting a TFTP server in Windows
Installing and Configuring a TFTP Server in Ubuntu
Connect to the switch via telnet or console and see the firmware information:
show firm info
If the bootloader is old, then it can be updated by executing the command (ATTENTION! Factory settings will be reset!):
download firmware_fromTFTP 192.168.1.1 src_file DES-3528_Series_FW_v1.03.B013.had
Actually, the firmware itself can be downloaded to the switch with the following command (the settings will be saved after updating the firmware):
download firmware_fromTFTP 192.168.1.1 src_file DES35xx_3.10.B052.had image_id 2
Let’s make the downloaded firmware the main one:
config firmware image_id 2 boot_up
Reboot the switch so that it starts with the new firmware:
reboot
That’s all.