mentech: [Hardware Mod][Teclast x98 plus II] Improving WIFI connection

WARNING! Hardware mods can brick your tablet even faster and deadlier than software, so please read carefully.
I am not responsible for your bricked tablet.

As I promised, I will share my experience about my attempts to improve the WIFI on my Teclast X98 plus II(C2D4).

A lot of users reported very bad WI-FI with this particular model, and the reason is simple:
The metal back cover! It simply shields the internals!!!. And we need to find a way around it.

First Step: Open the tablet

Have a plastic guitar pick and a cutter around
Try to find a gap to insert your pick
If you can't find a gap to insert the pick, slowly insert the cutter on the top of the tablet where the plastic strip is, and then insert the pick
Don't use the cutter to open, because you will make dents into the plastic
Don't force anything, be patient
After you inserted the pick, and you poped one part, the rest will follow
Don't insert the pick too deep and be extra careful with the cutter

Background: I live on the second floor, and I have a router on the first floor:
Speed before the mod: up to 5 Mbps

Now once the tablet is open we can see the internals, and it looks like it has plenty of space. We are interested in this part, the WIFI antenna:

Notice marking on the board: wifi plus(+) and minus(-)
First thing that I thought, is that maybe there is short between them. I checked with a multimeter and it was none.
I powered the tablet and did a speed test: the speeds were amazing!

So I started to experiment. There were multiple attempts but only two I found good enough.
Step TWO: Hardware mod

1. The basic way

You need only a pair of tweezers
You tweezers to unglue the tip of antenna
Be patient, do not apply to much force, the adhesive is strong but it slowly gives up
after the slim part of antena is free, make a fold 90 degrees up, so it will stick out of the case
Do not fold to agressive, the antenna doesn't really bends that way, so be carefull not to break it
make sure that antenna is not in the nearby clip and close the case
antenna still has adhesive, so glue it back to the screen

After you followed the steps from above, you should get something like this:

It is not very nice, but rather than an unusable tablet, this one is pretty good. Also, make sure you are not touching it when you use the tablet.
Speed after this mod: 5-15Mbps

2. Soldering extra wires
Warning! Be extra careful, while is not very difficult to solder on our tablet, I still recommend you to try to solder something before starting to work on the tablet.
You will need:

Soldering iron
Soldering supplies
multimeter
Copper wire with plastic cover(internet cable is not very good, phone cable: good)
Tape

Steps:

Cut a piece of wire, around 5 cm long
Remove the plastic from one end just a little, so you could solder it
Remove the plastic from the another end, about 3 cm, so that the wires will be free
Solder the short end to the (+) of wifi
Check if there is no shorts between the + and -
check that the original cable actually connects to original antenna
(Optional) Unstick the antenna from original position and stick it to the back cover, see images for details
stick the antenna exactly as shown in the image
be careful, do not rush and do not twist to hard
Get the free end of the soldered cable out of the case
Carefully put back the cover, with the copper wires sticking out
Do not press the cover fully, leave the top area a little open
Insert the thin wires between the gaps(as close to outside as possible)
Do not let the copper wires touch the metal back cover, twist them more to the center
Tape all connections, so it will not short with back cover!!