An old trick that wasn't very popular in the first place, not very good marketing material. Huawei was the starter and arguably the only contestant of the ISO race on the smartphone side, and they already gave up after they reached this number without the actual shutter speed to back them up(it was a stack with an effective ISO of the combined exposure of around 4096). Nobody else really took them up on it aside from Sony, but Sony's was basically hardware gain(how it's always been) while Huawei was the only one to really try to manipulate the scale with software. This now still looks like software, ISO102400 at this sensor size is unlikely to be hardware based, ~2 years after anybody else paid attention.