I can't predict or reliably reproduce the crashes. There are no error messages. If I bring up the recent apps menu, Firefox is there but the image has a black webpage. In contrast, if Firefox has not crashed, the image has a mini version of the current webpage.

I should mention that I wonder if the tablet has a hardware problem. I first suspected this when Kodi failed to start, but presented the error message: "Error! Cannot parse CPU features". That said, Opera beta runs fine without crashing. I don't use Chrome, so I have no info there. All other apps run fine. I've uninstalled/reinstalled Firefox. In fact, I've done a factory reset just because I thought it would be a sure fix - it wasn't. Please help with any guidance on troubleshooting, diagnostics, or anything that you think I should try. Thanks for your time in just reading my post.