Possible omnibus boot button fail

tried flashing new pro V3 last night using Win 10 …thought I had it but never got beyond message ‘erasing’. waited good three minutes but no other message. After about a dozen attempts holding boot button down while powering up via USB no longer saw DFU but just COM. Then Boot button seems stuck down! Anything I might try to remedy all and get this new board flashed with iNav? Normally run Linux Mint so am going to try that today instead of WIN10. Just think that stuck down boot b will be a problem! Note: tried Betaflight to flash as someone on forum said he had luck doing that after iNav flashing failure and Betaflight indicated read only and he said it got beyond that and successfully flashed…then he went back to iNav and then it also succeeded. No such luck for me! With Betaflight never saw DFU. only COM or Manual…nothing but stuck in th ether…where next?