However, if your device is “repeatedly rebooting,” the update “may not enable data to be recovered.” For those users today, Google’s temporary workaround is a Factory Data Reset: “This will clear your device’s storage, so we only recommend this if you have recently backed up your data. FDR can be completed even if your phone is repeatedly rebooting using the device’s buttons.”

Guess as of today there’s no fix yet for those stuck there.