tools required:

• soldering station + solder
• STlinkv2, clone will do fine
• somen wire (for v1 board)

this mode can be split into 2 main steps:

• upgrade SW
• modify HW

SW upgrade

todo add link after test of this howto: follow this how to

The first step is to change the bootloader for fastboot version which does not wait three seconds after reset to run user code instead, it starts it almost immediately. Follow instructions on this page to upload the bootloader to your module.

The next step is to re-upload SW to the module, follow this link with instructions on how to connect and compile your own firmware, or you can use precompiled binaries, links to these binaries plus how to do that, is on the same page.

HW modification

remove the led, this will take 3.3mA from the constant module consumption. This modification will disable the indication of 3.3Volt power present, because of this, preferred mode then the removing of led si to change series resistor for the led from 1kilo ohm to 10kilo ohm, but this requires 10k resistor in 0805 SMD package which you can not have on hand

TODO: add pics

There are four versions of the boards, look at this article to identify the version of your module.

Fix for V1 board:

Fix for V2 board:

Fix for V3 board:

Fix for V4 board: