From: Rabbi Akiva Eiger
To: Unknown recipient
The Chasam Sofer writes to Rabbi Akiva Eiger sharing his response to Rabbi Zalman Margolios of Brody, who sought to use the Ra'avan's ruling validating left-foot chalitzah b'dieved as a supporting factor for leniency in cases of iggun. After extensive Talmudic analysis, the Chasam Sofer concludes that the Ra'avan's view cannot serve even as a secondary basis for leniency, since no other authority adopted it, and relying on it against the consensus in a Torah-level matter could lead to disastrous consequences.
Source: Shu"t Rabbi Akiva Eiger §122