GoAhead Web server returns empty response


I am having a obscure issue with the CM 32 device running v1.9.5.3. The HTTP GoAhead web server allows to login to the admin console, and then starts sending empty responses. Restarting the device does not solve the problem. Attempting to activate any option in the admin menu results of empty responses. Occasionally, it starts sending empty responses if I try to reload the login page without entering any credentials. Has anyone experienced this issue?

The configuration via SSH CLI and configmenu works all right.

I would like to update the device to the last and latest 1.9.7, and doing it via HTTP is the easiest way, however it is not possible at all. Any attempt to update via SSH console and Zmodem send of bin file does not function either. Tried connecting via primary EIA-232 using 9600 8N1, no luck as well. The device was cold reset from the previous configuration a few times and no help either.

I appreciate any help on that.