Disk Utility cannot join two partitions if the "upper" partition is removed. Without a third-party tool such as iPartition -
VersionTracker or
MacUpdate - what you would need to do is re-create the "upper" partition. Click on the Add [+] button to add a partition in the "upper" gray space. When that's completed clone the "lower" partition to the "upper" partition using the Restore option of Disk Utility:
Clone using Restore Option of Disk Utility
1. Select the
destination volume from the left side list.
2. Click on the Restore tab in the DU main window.
3.Check the box labeled Erase destination.
4. Select the
destination volume from the left side list and drag it to the Destination entry field.
5. Select the
source volume from the left side list and drag it to the Source entry field.
6. Double-check you got it right, then click on the Restore button.
Destination means the Upper partiton.
Source means the Lower partition.
When that is completed return to the Partition tab of DU. Delete the "lower" partition. Put the cursor on the lower right corner gadget of the "upper" partition and drag the corner to the bottom of the sizing window. Click on the Apply button. When it's finished you should have a single full-sized volume on the drive with your data on it.
I suggest you backup the data just in case.
