to get ssh access on ls421de (stock firmware), follow this:http://forum.nas-hilfe.de/buffalo-techn ... t2165.html
Thanks Shadowro1999, I found the resolution, just format all and force update, after that, openSSH again and use the code from Oxygen8 wrote on this topic: http://forum.nas-hilfe.de/buffalo-technology-nas-anleitungen/ls420-serie-root-kennwort-wird-von-buffalo-ueberschrieben-t2232.html
The code to create backup password Oxygen8 give me in this topic did not work and I try a new code from his topic, it works perfect and I am not loose my password any more. I just install Aria2 on my LS421DE but I cannot find the way to connect with the remote, if you can please help me. Thanks a lot.