The bug would cause a7R IIIs and a7 IIIs to stop functioning while writing data to a previously used card. This would result in image corruption, preventing playback. So this new firmware update will fix that issue. Additionally, the firmware will fix the problem where the cameras fail to recognize third party memory cards.
The bug didn’t corrupt all images
Sony warned a7R III and a7 III users about the bug a little over a week ago. Luckily, those that were affected didn’t lose a ton of work. Users would often lose just one image. Some did lose a couple of images though.
It seems like the larger issues were related to reusing an SD card and using the auto review function. Thankfully, the cards often still preserved most of the data put onto it. The data could then be recovered.
Recovering your image
If you have experienced this bug, Sony has released instructions to recover your images if they aren’t displaying:
Select MENU → (Setup) → [Recover Image DB] → desired memory card slot → [Enter]. After that, take a picture, backup your data and format the memory card on your camera.
Are you affected?
If you are currently using V2.0 firmware on the a7R III and a7 III, Sony recommends you upgrade to the V2.1 firmware. If you aren’t using V2.0, users can upgrade to V2.1, avoiding the problems in V2.0.