[Android Q&A, Help & Troubleshooting] Skeah:
Hey ho, i hope i do this right and i am in the right section for this.

Device: Smartbook S7 Tablet(

not the Surfer!

)

Android: Jelly Bean 4.2.2 (exdroid4.2.2_r1-a23-v2.0)

SU: no SU permissions at the moment

Problem: adb shell gives a "-exec /system/bin/sh permission denied(13)"

Also i am NOW (after two month work trying to unbrick the shell) stuck in Bootloop for normal Boot

Ok, lets tell the story of my device:

I wanted Puffin Browser ... it told me to deactivate GFX Accelleration and i did but it still told it was on and refused to work with me or my tablet ...

SOOOOOO:

I tried to root this device (to sniff deep into it) and in the process i seem to have made some mistakes, due to my impatiance ... Problems at that time where that my wireless stopped working so i tried to find out why and found out, i was not able to start shell over adb anymore (wich had nothing to do with not working wireless as far as i found out), and the terminal app on my tablet started crashing even when i only tried "ls"

All other ADB commands are working so far, so i thought exchanging the sh file in /system/bin with adb pull (from adb emulator) and adb push (to device) would help but didn't solve anything still same error, then i started reading loads of articels, nothing worked so far but i am now able to root and unroot my GF's Phone in no time with almost no effort anymore ..... still can't unbrick my device .... it's been two months now, that i tried to unbrick it myself (i am a developer and just can't put it away unless problem solved ^^) but i am at the end of my knowledge and possible google commands ...

In the end my problems are "just" these:

1. The device is not listed anymore on the vendor webpage therefore i can't download any stock roms, support is not answering so far on my e-mail and ... ye i don't like to phone so i haven't tried the Hotline so far ...

2. My device is so freaking unkown that there are no working twrp / Clockworkmod Roms available for it

(tried them with "fastboot boot <name>.img") and either my bootloader just do not want to load them (S-ON i think can not check ...) or i am just not done trying ALL of em ... but half through the list of both ...

I also tried the Allwinner A23 images since it seems i have some kind of A23 Device ... but none of them with wireless have the matching screen resolution for example ...

3. i am not sure about fastboot working properly, cause it did not list my device when i type:

"fastboot devices"

i only get a blank line but it will list it when i specify it with the -i option

"fastboot devices -i 0x1f3a"

gives me:

"Android Fastboot fastboot"

and yes iam in Bootloader via "adb reboot bootloader" (adb reboot-bootloader didn't give me another Bootloader)

also i can fire fastboot commands like "fastboot oem unlock -i 0x1f3a" and "fastboot oem lock -i0x1f3a" but "getvar cid" for example gives me: "cid not supported"

4. My Bootloader only shows me the Android Symbol and there seem to be no Key Combo to get in it without adb O.O or at least neither the manual nor the try outs of "standards" got me anywhere else then in normal boot or recovery mode ...

OK until two days ago the device was booting until the end, just had no working shell and no wireless now i made a change in vold.fstab pushed it on the device and boom got stuck in bootloop. So i tried pushing back the original i saved, still bootloop. Only thing logical that may have changed on the original file are the permissions, so i guessed the same thing happend to my sh during root attempt (i tried quite some stuff that day so i can't really remember at what point shell stopped operating) so i downloaded CYGWIN and pulled the whole /system into it "ls -l" then showed me that all pushed files had wrong permissions on it, so i can push/pull files but i can't give them the right permissions ....

I really tried many things, "googled" until my fingers where bleeding, read until my eyes burned and thought until my head began to smoke but i just can not find a solution and in my opinion the only thing i need, is to get back shell access OR a stock system rom i can flash via fastboot (the flash option would work)

Thanks for any help and i hope the above text is not too much of a mess and i ap(p)ologize for my english, unfortunately it is not my native language.