This only applies to the original batch of TinyHawk drones manufactured in late 2018. If your TinyHawk has a capacitor near the bind button, as seen in the photo below, this article does NOT apply to your drone.
If you are experiencing brownout issues with the original batch of TinyHawk drone, essentially what is happening is that the flight controller's MCU is locking up due to low voltage (it is not the receiver). The MCU can only operate down to 3.0V-3.2V, so when your battery drops that low it will start to lock up. Or, if you have a bad battery that sags below 3V during high throttle surges you will experience the lock up sooner. Originally, the TinyHawk was designed such that one could not fly the battery to below 3.3V in order to help extend battery life. However, if you prefer to go below that voltage the following modification will help.
One can put a capacitor between the 3.3V and ground pads on the flight controller. These two pads are available on the bottom of the board near the Bind button. The pads just need to be bridged with a small capacitor, such as a 10uF ceramic capacitor, or any other larger electrolytic capacitor (watch polarization). Basically this capacitor will hold enough charge to keep the MCU powered when the battery dips below its operating voltage during high current demands. This modification will allow one to run the flight battery to 2.8V, albeit at a severe cost to battery life. Emax does not recommend doing this as the battery cycle life will be dramatically reduced.
You are also welcome to send in your TinyHawk for our techs to add the capacitor. Alternatively, we can also send you a ceramic capacitor if you cannot find one readily.