The revised partition deed has no legal sanctity if it is made for the partition of the immovable property and it is not registered. Go through the TP Act and Contract Act.
But if it on stamp paper and not registered then he cant challenge.
The legal position is as under:
1. Partition is severance of joint status.
2. Partition can take place in two methods (i) orally and (ii) through document.
3. Parties can make a private partition orally in respect of immovable property.
4. Parties can also make a partition by executing a registered deed.
5. A memorandum or acknowledgement of a partition already effected orally does not require registration, since it does not create any right in any property and its registration was not compulsory.
6. However, if by that very document the will to separate and the manner of the partition is to be deduced, then it is compulsorily registrable.
7. A deed of partition is compulsorily registrable under Sec. 17 of the Registration Act, 1908. A non-registered partition deed will not be admissible in evidence.