I have a Netgear cradle DC112A. When using Netgear Genie it tells me the Firmware Version is V1.0.0.42_1.0.60. Doing a firmware version check gives the message "No new firmware version available". I am aware that this is not up to date and I have downloaded the latest version from your ZIP file which unzips to DC112A-V1.0.0.54_1.0.60.chk (with 13,505KB).
Using the Advanced\Administration\Router Update facility, selecting file DC112A-V1.0.0.54_1.0.60.chk and "Upload", I get the message "This firmware file is incorrect! Please get the firmware file again and make sure it is the correct firmware for this product."
Is a .CHK correct? This is generally the file type for "recovered file fragments".
