This etimology is not new:

PN *buk'- / *bok'- 'to bend'
PIE *beuk'- > *beuk- 'to bend' (traditional *bheug-)
PAL *bükä- 'to bend'
PAA: Proto-Omotic *buk'a (¿?) / buka 'knee (< ¿bend your leg?)'

Cf. IS nº 25 *bük.a

I agree with Bomhard's methods, and some IS's etimologies are not
reconstructed by them. By the way, I do not think that Pre-PIE have
voiced aspiratd stops.

¡Por favor, que alguien me escriba en español o si no voy a pensar
que sor el único que estudio nostrático en España!