You could try a deep update.
Put the Core in DFU mode by holding down both the RST and MODE buttons, releasing RST and continuing to hold down MODE until it blinks yellow and issue the commands below, in order.
After completing some of the steps the color may change to something else; if so note what color/pattern it is, then use the button combination to get back to blinking yellow. The core should be blinking yellow before each of the commands listed below is entered.
particle flash --usb --factory tinker
particle flash --usb deep_update_2014_06
particle flash --usb tinker
particle flash --usb cc3000
particle flash --usb tinker
Then put the Core in listening mode (blinking blue) if not already in that state by pressing and releasing RST. Then holding down MODE until it blinks dark blue. Then issue the command:
particle serial wifi
The normal sequence is white, blinking green, blinking cyan (light blue), fast blinking cyan, and finally breathing cyan. If you do not get to breathing cyan, please copy and paste the terminal output in your reply and let me know how far it did get.