RPI Mini Router

I am having trouble upgrading to latest firmware image.
Any of your images with kernel 5.4.179 work fine but 5.4.188 fails to boot successfully.
White light blinks forever, video output shows filesystem problem.
I have tried different dated releases with Rasperry Pi Imager, Balena Etcher, Windows, Linux. All the same results. If I revert to a 5.4.179 image it works instantly.

Images come from here:
https://onedrive.live.com/?authkey=!AEcwsyZAovIBK-I&id=5219529519B9B6A1!963&cid=5219529519B9B6A1

Any ideas on how to fix this?
Thanks.

Does anyone know how to get support for something like this? I would think company reps wuld be involved in this.