I don't think there's available bypass firmware for this unit; I've never heard of any since before. So I believe it does not exist.
However, google pointed me to this site
https://bixbit.io/en/firmwares/whatsminer-series-m3xBut the problem is this is not a well-known site here on the forum but they had thread here on the forum "
BiXBiT Dev custom ASIC Whatsminer firmwares: optimize performance & efficiency"
It might work, but I can't guarantee that their firmware doesn't include hidden fees.
Would you mind telling us more about the issue? Which board exactly did you replace? Control board or hashboard?