From: Rabbi Moshe Sofer
To: Rabbi Asher
A scribe glued margin strips from invalid Torah scrolls as reinforcement patches onto a valid Torah scroll. The Chasam Sofer rules this was improper, as transferring margins from one Torah to another constitutes a degradation of sanctity. However, the valid Torah scroll is not invalidated by the patches, since the patches are supplementary and the principle of na'aseh ba'aveirah does not apply; the patches should be left in place as their genizah, and the scribe should repent.
Source: Shu"t Chasam Sofer YD §279