Not answering your questions about down-grading, but… breathing magenta is safe mode. If your photon boots and continuously goes to safe mode, there is a problem with your application that causes the Photon crash.
@chipmonk, the default target used by the CLI is the latest release version, aka 0.7.0. If you want to compile to 0.8.0-rc.8 or later, you would run particle compile photon --target 0.8.0-rc.8 . for example.
@chipmonk I think you need to get the web IDE working first with your libraries and 0.8.0-rc.8. I have experienced some funny behaviour with 0.8.0-rc.8 and 10. When in the web IDE with the target photon online (breathing cyan) and the device selected (yellow star) what on device firmware is showing? Try selecting target 0.8.0-rc.8 and doing a compile then fix any library issues.
If you can USB connect photon then put it in listening mode (flashing blue) and try particle serial inspect. This will identify if any odd modules - I have had bootloader incompatibility issues which usually can be cleared with particle device update or particle flash serial "bootloader-0.8.0-rc.8.photon.bin",
Lastly, 0.8.0-rc.8 requires CLI version 1.33.0 (and as confirmed by @rickkas7 this has some bugs in it with wifi security setting).
I need someone to give me a couple of details on how to downgrade the particle that is currently running 0.8.0-rc.8.
Looking a the Git Hub I see some text on downgading this version 0.8.0-rc.8 os as follows.
Note: Downgrading [Electron/Photon/P1] OTA or YModem transfer: If you need to downgrade, you must downgrade to 0.7.0 and then 0.6.3(Photon/P1), 0.6.4(Electron) to ensure that the bootloader downgrades automatically. When downgrading to older versions, downgrade to 0.7.0 first, then 0.6.3(Photon/P1), 0.6.4(Electron), then to an older version such as 0.5.5.
So the procedure as I understand for a photon is using the dfu serial mode
Now do I flash the bootlooadeer
Then it appears I need to repeat this with 0.6.3 system.part-1 / system.part-2
Do I have to reflash the boot loader ?
Understand I am a hardware guy and don’t like to flash things unless I am 100% sure what I am doing will work. Silicon bricks are a pain to restore
There are official (not RC) release binaries available for 0.7.0.
However, if you just run particle update in DFU Mode the Device OS should be rolled back to 0.7.0 - providing you first flashed a user application that doesn’t trigger an auto-update cycle immediately after that. Hence it’s advisable to run a particle flash --usb tinker first (assuming these are not “product” devices).
BTW, these devices aren’t that easily bricked just by flashing wrong binaries.