If using Windows, install 'nodemcu-flasher'.
Use the following two bin files.
Note. These may not be the same files as others posted elsewhere with the same filenames.
The first one loads at 0x00000. The second at 0x40000. You need to add these files in the first two file boxes in the nodemcu-flasher config menu (blue blob) and set the correct load addresses from the drop-down menu. Uncheck any other boxes in the menu. (The default is 4) . Check you have the right COM port. The program gives you the options, no typing needed. (The whole process needs no typing at all !)
Make sure the ESP is in boot mode (GPIO0 = 0) Then go back to the main menu and click on Flash.
This programs the ESP correctly and now I can use the AT V0020 command set and firmware 0.9.4 - at last. All the V0.2 AT commands are fine. I run at 115200B OK.
Regards
Mike