Reset Partition Table for Nexus 7 2013 (Flo)
I was in the same position as you re a total resizing of the partition table > System to Data.

The following posts will help you.  The first is a script to recreate all the required partitions.  The second is a method to get the bootloader functioning from a Hard Brick.

Worked on this for hours last night and have now had successfully recovered back this morning.

Good luck.

Mo

https://forum.xda-developers.com/showpost.php?p=75465233&amp;postcount=222

https://forum.xda-developers.com/showpost.php?p=75360854&amp;postcount=199