Internal system RO(read-only) and no OS - Android Q&A, Help & Troubleshooting

Hi, guys! New user here and let's start!
Well, I own a tablet which the model is Innovator 7DTB41...
I bought it from Greece!
Although I found out that model's name varies at Amazon which there is named Hipstreet 7DTB41-8GB Electron 7" (Quad Core 1.3GHz Google Certified Android 5.1 (Lollipop) Tablet 8GB -Black). I'm sure 99% that Amazon's link have right specs with the other link from E-shop that i bought it!
The images from Amazon, like volume button, power button, port micro USB, port auxiliary are the same position with my tablet! If that tells something!
At first, the tablet was rooted to remove bloatware, and I tweaked the build.prop...The tweak settings I'll write them below... the problem is that suddenly the internal storage went from (read-write) to (read-only) and when I was changed back to read-write with ES file explorer it didn't do something.. So I decided to give a reboot if this fixes the problem...After the reboot, the OS disappeared and more simple it does not boot...
Also, it has recovery and I just boot into that! The choices that were given to me is 7
Android system recovery <3e>
7DTB41_20170119
1. Reboot system now
2. apply update from ADB
3. wipe data/factory reset
4. wipe cache partition
5. reboot to bootloader
6. power down
7. View recovery logs
Recovery system v5.0
E: failed to mount /mnt/internal_sd (No such device)
Tweak Settings:
#Faster Scrolling
ro.max.fling_velocity=12000
ro.min.fling_velocity=8000
#Liquid Smooth Ui (not the custom rom)
persist.service.lgospd.enable=0
persist.service.pcsync.enable=0
ro.ril.enable.a52=1
ro.ril.enable.a53=0
#Better internet browsing & download speed
net.tcp.buffersize.default=4096,87380,256960,4096, 16384,256960
net.tcp.buffersize.wifi=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.umts=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.gprs=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.edge=4096,87380,256960,4096,163 84,256960
net.tcp.buffersize.hspa=6144,87380,524288,6144,163 84,262144
net.tcp.buffersize.lte=524288,1048576,2097152,5242 88,1048576,2097152
net.tcp.buffersize.hsdpa=6144,87380,1048576,6144,8 7380,1048576
net.tcp.buffersize.evdo_b=6144,87380,1048576,6144, 87380,1048576
# Saves some battery without reducing performances
wifi.supplicant_scan_interval=497
pm.sleep_mode=1
power.saving.mode=1
ro.ril.disable.power.collapse=0
ro.vold.umsdirtyratio=20
# Increase general Performance
debug.performance.tuning=1
# Increase some Performance
ro.secure=0
persist.sys.use_16bpp_alpha=1
ro.product.gpu.driver=1
ro.min.fling_velocity=8000
# Reduce the black screen time of the proximity sensor
ro.lge.proximity.delay=15
mot.proximity.delay=15
# Increase camera's photo and video recording quality
ro.media.dec.jpeg.memcap=8000000
ro.media.enc.hprof.vid.bps=8000000
ro.media.enc.hprof.vid.fps=65
#Better RAM managment
ro.HOME_APP_ADJ=1
Disables built-in error reporting.
profiler.force_disable_err_rpt=1
profiler.force_disable_ulog=1
#Disables logcat
logcat.live=disable
#Faster boot.
ro.config.hw_quickpoweron=true
#Disables error checking.
ro.kernel.android.checkjni=0
ro.kernel.checkjni=0
#Disables sending of usage data.
ro.config.nocheckin=1
#Disable strict mode checking.
persist.android.strictmode=0
#build.prop tweaks for improved performance
debug.performance.tuning=1
Thanks for reading until now!!
Sorry for any mistakes! I cannot put links! :/

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angel1998 said:
So I decided to give a reboot if this fixes the problem...After the reboot, the OS disappeared and more simple it does not boot...
Also, it has recovery and I just boot into that! :/
Click to expand...
Click to collapse
Γειά σου φίλε!!!
Have to keep it in English though for everybody to understand. If system partitions got messed up trough the process you described, well... Chances are you might need to flash full stock...
However... Since you can get to stock recovery, can you do a factory reset? Does it work? Or does it come back giving you a whole bunch of red lettered errors? If that is the case full stock flashing is the solution...
Unfortunately, I personally can't think of a way to make this work without losing your data. But, hey... You won't through away the device!!!
Post a little more info if you wish, or update on how you are doing with the device, so others can also help. Also please check your private messages.

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Well, guys, I gave up, cause Windows doesn't recognize the tablet in download mode or in bootloader, and I had to mess finding drivers which are not easy with this whatever brand name is and i sent it to the shop i bought, and they will give me a replacement!
Special thanks to r&xp for helping me at private messages!