I was recently contacted by a fellow Swiss IoT hacker about a new offering to transfer the NodeMCU firmware to ESP-01/07/12 modules. He created a self-contained hardware setup that allows you to easily to plug in those modules for the data transfer. There’s a Kickstarter campaign currently running to develope it beyond the state of a clever prototype.
The modus operandi is quite simple:

• Plug the ESP-01/07/12 into the programmer
• Connect the programmer to the USB port of your computer
• Optionally hook up the programmer to an external power supply
• Choose whether you want to upload application data (Lua, with e.g. ESPlorer) or to flash firmware

Two quotes from the Kickstarter campaign

[…]What is still missing is convenient and robust hardware tools to connect ESPs with the powerful SW already available like e.g. Esplorer, Luatool, Esptool and many more. This project aims at making a robust and reliable programmer for the ESP01/07/12 so makers can save their precious time for what they like to do most: Innovate!

One of the main problems on many computers is that USB ports do not supply sufficient power, so this tool allows to optionally connect an external power supply. During my work with the ESPs I struggled to find a USB to serial adapter which works across all platforms. The unit supplied is the best I found (CP2102 based).

The device seems really well thought out and is surely helpful for a certain group of people. Keep in mind though that in most cases an ESP8266 without any sensors or actors connected to it is barely useful. Hence, at some point you’ll need to start tinkering on breadboards anyway and issues like stable power supply will need to be addressed. If you need to quickly prepare a small batch of devices the programmer may come in handy.

Disclaimer: I’m not associated with the creator in any way, we never met. I don’t have access to a prototype. Therefore, I wasn’t able to test-drive the programmer.