It seems Microsoft inadvertently pushed Windows 10 Builds to both PC and Mobile from branches it wasn’t supposed to release. Not only insiders but even non-insiders saw Builds being offered to them, though non-insiders, fortunately, were not able to install them. Insiders who were able to install offered build bricked their phones.

Microsoft has offered solutions for those who bricked their Phones by installing the Build from RS_IoT branch. If you managed to install this build you need to revert by using WDRT. Check our tutorial to learn how. If you have not installed this build yet but downloaded you need to do a hard reset to get rid of it. Non-insiders may see this build but won’t be able to install.

While those on PC who installed these builds need to either roll-back to the previous build or wait for a new build. As per Microsoft, you have up to 10 days to roll-back and this will only work if you did not do Disk Cleanup to remove your previous Windows installation.

Once you have rolled-back or done re-flashing using WDRT you need to re-join Windows Insider program and check correct ring as per your risk-affinity.

Source: Microsoft