No audio after Big Sur update on ASRock Z490 / AppleALC 1.5.4?

Hi,

• ASRock Z490M-ITX/ac
• Intel i7-10700K
• OpenCore 0.6.3
• AppleALC 1.5.4

I just updated to Big Sur and all* went smoothly - I left the process running cia Software Update and returned to find a Big Sur login screen.

*However I now have no audio. According to the release notes for AppleALC, native support for my motherboard was introduced at v1.5.2 ("Added ALCS1200A layout-id 49 for Asrock Z490M-ITX by VanXNF").

My Opencore bootargs in NVRAM are -v alcid=49 keepsyms=1 and my kexts are as follows:

• USBPorts (1.0)
• AppleALC (1.5.4)
• VirtualSMC (1.1.8)
• Lilu (1.4.9)
• IntelMausi (1.0.3)
• USBWakeFixup (1.0)

I'm a bit out of ideas - can anyone suggest something I can try to fix this please?

Thanks