A few people have been converting Spektrum radios to work with the Chinese DIY modules (such as those from Assan, Corona, FrSky, Fly-Dream, etc).
With some of the Spektrum transmitters only using a 4-cell battery pack, it is difficult to meet the minimum 6V power requirements of a DIY kit like the Corona. What's needed therefore is a way of stepping the 6V up to the 9V or so that these modules need for reliable operation.
Today I found this little gem on the Himodel website:
2.5-25V Input, 3-25V Output Step-up Voltage Regulator
If it works as advertised, it could be a useful way of getting enough voltage for any DIY module that isn't happy with 6V.