Apparently, Yoichi Miyaoka made a serious attempt to prove FLT in 1988. See the following question.
In that question and another previous question, it was asked whether references for his proof exist. Shockingly, not a single trace of the original mathematical texts seems to be available anymore. This is a sad situation, since it means we cannot learn from his attempt at all.
My question is about the works mentioned in the Barry Cipra article quoted in the above answer:
Parshin showed that the arithmetical version of a certain inequality involving geometric invariants of surfaces—an inequality that Miyaoka proved for the geometric case in 1974—would lead…
Miyaoka had "a very interesting idea" to replace the tangent bundle with a "generic" bundle … Miyaoka has carried the idea of substituting generic bundles for the tangent bundle back to the original geometric case.
Please see here for the full quote, I have just bolded the parts I am asking about to avoid duplication of the entire thing. I would like to have references for the work mentioned in the first part, which I am sure experts should be able to provide. (I apologize for my lack of proper background) More optimistically, for the second part it seems that some interesting idea was salvaged and I really hope that there is some reference for it still existing. It would be a real shame if this idea is lost for ever.