Increase size of ext2 beyond 1.5GB
Here's how I did it when I needed to increase the size of my second  (ext2) partition that Link2SD used for applications from 2GB to 6GB:


Use free version of Mini Partition (v9.1) to


a. shrink the first partition (FAT32) by 6GB 
b. ensure the existing 2GB ext2 partition is at the end (so that the second space after the first partition is the now unallocated 6GB space)
c. create a new 6GB primary ext2 partition in the unallocated space

Use the free version of Paragon ext2fs to mount the 2 ext2 partitions in Windows and allocate each a driver letter
Use Windows explorer to copy the contents of the old 2GB ext2 partition to the new 6GB partition
Put the card back into your phone and have Link2SD recreate the mount scripts for the 'second partion' (just to make sure the 6GB one works)
Use Mini Partition to:


a. delete the old 2GB ext2 partition
b. move the 6GB ext2 partition to the end of the card/drive
c. extend the FAT32 partition to fill the 2GB unallocated space.