Being of an empirical and somewhat adventurous nature, I decided to install the firmware labeled 1_52. The meter started back up just fine but comedy ensued, the firmware revision is reported as 1_53. I checked this several times lest my eyes deceived me. 1_53. I suppose I can state the result is better than expected, at least numerically.
Cursory examination, the meter seems OK. I'm still wondering if, after 1_51, it's still calibrated. but I think it is. I'd like a way to verify that - what a "bricked calibration" looks like is not what mine looks like. I'm thinking that the incident that initiated pulling 1_51 was fairly anomalous but can we get confirmation?