Factory Reset for M2826 Express Laser Printer?

I misunderstood a setting and configured my Samsung M2826DW Express Laser printer to only allow an admin login from 192.168.1.6, but I have a different router now and the printer and all my computers are on the 192.168.0.255 subnet now. This means I cannot login to the printer to change anything although I can still access its web page. I just can't login. I would like to do a factory reset of the printer to correct this problem. I searched the internet and found several sites offering to sell me a special firmware update to do this but I don't know if they are trustworthy, so I have not purchased it from one of them. I am reluctant to run binary software from an untrusted source. Hopefully, it won't make a difference, but my notebook runs kubuntu 18.04 Linux. I have access to a Windows 10 notebook if necessary.