If you have the Particle debugger you should be able to restore the bootloader and DeviceOS.
Relevant threads:
https://community.particle.io/t/boron-stuck-in-dfu-mode/46269/2?u=nrobinson2000
https://support.particle.io/hc/en-us/articles/360039251414
Additionally, @rickkas7 can be a lifesaver in these situations.
I’d recommend opening a support ticket.