As @johan_m_o states, you are supposed to first boot into the bootloader mode (the one with =====).
After that search the device in the NRF toolbox, but it will not show up as Bangle.js 31f1 but as Dfutarg. Selected that and it should be working fine.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
As @johan_m_o states, you are supposed to first boot into the bootloader mode (the one with =====).
After that search the device in the NRF toolbox, but it will not show up as Bangle.js 31f1 but as Dfutarg. Selected that and it should be working fine.