Looks like a new 2.52 version of HX Edit and a new 2.52 firmware has been released.with some bug fixes. A really fast response, thank you Line6! Would suggest to anyone upgrading to follow this procedure and of course Line6's latest installation instructions:
Get backups with your current version of HX Edit just in case. I personally go overboard and get an HX Edit full backup, as well as backing up my IRs, a bundle, separate setlists, and separate presets. However the new HX Edit software only actually marginally requires the full HX Edit backup - if you don't care about updating the Factory and Template setlists to the latest it will actually do an update in place retaining all the old setlists. So theoretically you can upgrade from 2.51 to 2.52 without a backup but I still feel better having having them(highly recommended at least get the full HX Edit backup, it would be foolhardy not to). Btw, the onscreen instructions when you run the Updater also say to get backups with the HX 2.52 editor as well before upgrading the firmware. I actually exited the Updater when I saw this and brought up the 2.52 editor and got a backup before returning to the Line6 Updater for the firmware update.
Don't download the Flash(firmware) file or Line6 Updater directly. Instead download and install the correct version of HX Edit 2.52 for your device which will unpack the Editor, Updter, and driver for you.
Use the 'Line6 Updater' to upgrade to the 2.52 firmware. Click on the initial screen of the Updater which will show a picture of your device with your current version of your firmware, not the new version. This assumes your device is connected via USB to compatible hardware with a supported OS . Make sure you don't have the Editor and the Updater up at the same time. After you click through the initial screen the Updater will then give you a choice of the new 2.52 firmware. Just point and click and let the Updater walk you through the firmware upgrade. Follow firmware release instructions provided by Line6.