I had a similar behaviour when having 9006 error. Just pressed 12-15 seconds power button. Then, you have to try to keep it powered off and unconnected. Afterwards, just press Vol+ button and connect via USB w/o touching power button.
In that moment windows should show and interface, this is the moment to attach as a Qualcomm 9xxx interface. Please, tell us which interface does appear and we'll be glad to help you here.
Hope you are lucky and find a 9008, anyways you are likely to restore your dev.
I thought that this blinking red led was due to a low battery mode, you have to achieve static blue led (programming mode).
Good luck