Microsoft has released SQL Server 2008 R2 Service Pack 2 Cumulative Update 1, which is Build 10.50.4260.0. This CU has 35 fixes listed in the public fix list. This CU should get the SQL Server 2008 R2 SP2 branch aligned with the fixes in SQL Server 2008 R2 SP1 CU7, although I don’t have official confirmation of that yet from Microsoft. That is the normal pattern, where a new Service Pack is quickly followed up by a CU on the new SP branch that includes the hotfixes for the last couple of CUs on the previous Service Pack branch.
At least one important hotfix from SQL Server 2008 R2 SP1 CU6 is included in this CU, which is:
FIX: Errors when a client application sends an attention signal to SQL Server 2008 or SQL Server 2008 R2
As always, keep in mind that this Cumulative Update is only for SQL Server 2008 R2 Service Pack 2, not for earlier Service Packs and not for SQL Server 2008.