[G Pad 10.1 General] BlastMeOblivious:
Right, a mount data error occurs because TWRP doesn't recognize the file system of the userdata partition, which is ext2 at first due to mkpartfs only supporting ext2, but it is explained that as part of the installation process Candy5 should ignore it and install anyway and convert ext2 to ext4. When I tried to install Candy5 I was getting a 'E: failed to mount /data' error and Candy5 flash wouldn't even start, twrp was also recognizing internal storage as 0 because of the ext2 file system as well.

To resolve this, I ran '/system/bin/mke2fs -t ext4 /dev/block/mmcblk0p33' (where the number 33 is the number of your userdata partition) which is mentioned in step 29. After that, I rebooted recovery and then the data partition recognized properly and mounted in twrp and read as 16 gb. Candy5 then flashed perfectly and the rest went pretty smooth from what I recall, I may have also wiped dalvik after the factory reset in step 30 as well . Since you already installed Candy5 it should have converted it to ext4 already but you still mention the mount data error which is why I was curious what your partition table was showing.

If you are still having trouble with adb not recognizing your device when you try 'adb devices' then you may have a driver issue or something else going on. I believe some other people have had similar issues in this thread if your read or search through it you may be able to find an answer to that.

---------- Post added at 05:47 AM ---------- Previous post was at 05:25 AM ----------

I ran it right from the terminal emulator as well. When you try to print the partition table are you beginning with the parted command? So the full string should be 'parted /dev/block/mmcblk0 p' and 'parted /dev/block/mmcblk0 rm 34'. Now be very careful and make sure you look at the partition table before running the rm part as it just removes the corresponding partition so make sure the number reflects the proper partition as ymmv and you will be up a creek with a bricked tablet if you delete the incorrect partition.

Also, when I ran the mkpartfs I just put it all in one. I think I ran something like 'mkpartfs logical ext2 3439 15750' and then ran the name part to name it userdata. Again, be sure to follow the step in the guide and check the partition table to find out where the last partition ends after removing grow and userdata because if you just punch in 3439 without confirming that is the end then you could be overwriting part of a partition, and bricking your tablet. In my case the partition table looked exactly as the guide and the end of the last partition was, in fact, 3439 but I made darn sure I wasn't just taking the guides word for it and was checking to see what my own tablet showed before deleting or writing anything.

Lastly, if you aren't comfortable with the thought of bricking your tablet and you aren't comfortable with the commands, you may be better suited to not proceed. You are at the beginning of a pretty volatile section of the guide where a wrong command could easily end with you doing some irreversible damage. Not trying to be discouraging in the least or critical, just giving fair warning :cowboy: