In the article about Jinnah, Wikipedia says:
The British in May [of 1946] released a plan for a united Indian state comprising substantially autonomous provinces, and called for "groups" of provinces formed on the basis of religion. Matters such as defence, external relations and communications would be handled by a central authority. Provinces would have the option of leaving the union entirely, and there would be an interim government with representation from the Congress and the League. Jinnah and his Working Committee accepted this plan in June, but it fell apart over the question of how many members of the interim government the Congress and the League would have, and over the Congress's desire to include a Muslim member in its representation.
The footnote on this cites the book Jinnah: India-Partition-Independence by Jaswant Singh. This book explains the British proposal and the complex negotiations around it in much greater detail. It was originally published by Oxford University Press so I would consider it a fairly reliable secondary source. To include a brief quote here:
[Jinnah did] agree to a Federal Union government concept. This was a major concession as it implied Jinnah, if not entirely giving up, then was certainly diluting his demand for a sovereign Pakistan. Soon, however, he found that the Cabinet Mission had not sufficiently recognized the significance of this gesture. In return, Jinnah had expected the Congress to shed their policy of ‘grouping’, which they would not...
To answer the headline question then: sort of. Jinna indicated a potential openness to such a compromise. This was significant, but he didn't firmly commit to giving up his demand for a separate Pakistan.