Many thanks to huhai_1000 (caiyijun@hantek.com) for sending me the tools and directions for re-initializing my DSO3254A. It is now working perfectly!
Thank you and best regards.
This was finally fixed after seeing this thread with a newer release of the DSO3254a firmware than was sent to me in 2019. Happy to finally revive what had become a dead piece of test equipment, but disappointed that it took so long to get a solution.