<p>based on strings in the firmware, it looks like it's using this exact STM32 bootloader</p><p>the bootloader repo is over 300 MB in size because they checked in a build of an Android app that you can use to reflash the thing</p><p><a href="https://github.com/Embetronicx/STM32-Bootloader" target="_blank" rel="nofollow noopener" translate="no"><span class="invisible">https://</span><span class="ellipsis">github.com/Embetronicx/STM32-B</span><span class="invisible">ootloader</span></a></p>
