This page lists a pc util for flashing the S6 and also a list of all firmwares I have come across.
Bear in mind to use these you have to match with the correct Android app version, or crazy things may happen.
Dont use any of these unless you know what you are doing. As always there is a risk you can brick your craft.
These are only listed for experiment and archive purposes really, as you are best to use the latest version of app and firmware
As I have had quite a few questions on how to do this here is a Link to make it easier for people and with english instructions , please click on this link.
Firmware bin files for archival purposes
The flight firmware above – S6F70720 , was the last firmware update for the Wingsland S6. So after only a few updates over just a few months, there has not been any more and the quad has sadly been abandoned by Wingsland , so dont ever expect any further updates.