Not by default. You need to separately run fastboot oem unlock after flashing.
Search for “TOTOLINK E1200M firmware download” or visit the support page of your specific brand. e1200m flash file install
Browse to the folder where you extracted the E1200M firmware. Not by default
Some malware burrows into the system partition. A standard factory reset will not remove it. Flashing overwrites the entire system, eliminating deep-rooted threats. eliminating deep-rooted threats.