Wi-Fi connection lost with security Firmware V1.0.9.18_1.2.27 patch on R7000

After installing V1.0.9.18_1.2.27 on my R7000 router, I lose WI-Fi connctivity on both the 5 and 2.4 Mhz bands. The hardware Eithernet connections stay active, and otherwise the router behaves normal...