For some new users don't know how to flash ROM, This tutorial shows the whole process.
At first you need download the files to a new folder and remember the location then install

https://mega.nz/#!GFBTmS6L!CfCYLCjTCqNY ... fCRN4-RGEo

I tired to install the Y811_A1_UItra_V03_20150828, but nothing happened. Currently I'm using the previous Y810_A1_Ultra_V02_20150521 ROM.
Can I update to the new one or Y811 and Y810 models are different? Please advise. Thank you in advance.

both you can try.

both you can try.

Could you send me a step by step tutorial, how to do this? Have tried with the built in OTA updater as local update, but after the update nothing happened and it remained on the old rom. Why don't you enable the new rom as an OTA update? Thanks.

you can see
viewtopic.php?f=54&t=21

Thanks, working.

Could you please share it to BBS to help other users?
thanks