In the case of the Galaxy S8, there was a bug with the Snapdragon 835’s radio code that caused the phone to drop off from Sprint’s Band 41 LTE sooner than they would have to, and falling back to slower bands. The firmware update appears to have fixed that which means that users should be experiencing faster and more consistent speeds than before.
According to Ryan Sullivan, VP of product engineering and development at Sprint, “There was a miscalculation in the software that was reading the device, so it tuned away from Band 41 before it should. Working back with Qualcomm and Samsung, we quickly found it, diagnosed it, and launched the update on June 5.”
Note that these changes also affect the HTC U11 where based on the data, users are now experiencing an average of 27.9Mbps in download speeds, up from 19.2Mbps from before, so if you haven’t updated your phone yet, you probably should.