I guess you mean breathing white, right? Like shown here https://docs.particle.io/tutorials/device-os/led/photon/#wi-fi-off
This is the expected behaviour when using SEMI_AUTOMATIC mode.
And if it is in fact that then you should call WiFi.on() prior the Particle.connect() call.
While this shouldn't normally be required and will hopefully be fixed, it never harms actually having it there.
This is the respective issue filed a while ago.
https://github.com/particle-iot/firmware/issues/1631
Since the only response there seems to be countering my arguments for the "legacy" behaviour to be re-implemented, any support for my proposal to "fix" it would be welcome.
However, you can also always try Safe Mode to update OTA.
That would suggest there are no valid WiFi credentials stored. In order to store WiFi creds the WiFi module should be on too, but if your application doesn't power it on you could go into Safe Listening Mode.
BTW, reflashing the bootloader (which only works via --serial) wouldn't change anything in that respect.