adb result "error: device not found"

it has been a week i bought tablet SFT (smartfren AndroTab) S7 atau "skyworth 7", and do nothing for that ROM



its own OS ICS 4.0, i feel it has lag for screen..
when i read step for Rooting i've think it long step and hardway
first install adb, connect ur tab until "device manager" judge that unknown device..bla..bla..matching between file adb such as "android_winusb.inf" with HW Ids in devicemanager
insert
Smartfren Androtab
%SingleAdbInterface% = USB_Install, USB\VID_
%CompositeAdbInterface% = USB_Install, USB\VID_

second rooting process
1. C:\ADB> adb shell
2. shell@android:/ $ mv /data/local/tmp /data/local/tmp.bak
3. shell@android:/ $ ln -s /data /data/local/tmp
4. shell@android:/ $ exit
5. C:\ADB> adb reboot
6. C:\ADB> adb wait-for-device
7. C:\ADB> adb shell
8. shell@android:/ $ echo ro.kernel.qemu=1 > /data/local.prop
9. shell@android:/ $ exit
10. C:\ADB> adb reboot
11. C:\ADB> adb wait-for-device
12. C:\ADB> adb remount
remount succeeded
(THIS STEP UR SCREEN TABLET WILL BE BLANK)
13. C:\ADB> adb push su /system/bin/su
14. C:\ADB> adb shell

(if u find $ be # show that u've got ROOT ACCESS)

15. root@android:/ # chown root.shell /system/bin/su
16. root@android:/ # chmod 06755 /system/bin/su
17. root@android:/ # rm /system/xbin/su
rm failed for /system/xbin/su, No such file or directory
18. root@android:/ # ln -s /system/bin/su /system/xbin/su
19. root@android:/ # exit
20. C:\ADB> adb push Superuser.apk /system/app/
21. C:\ADB> adb shell
22. root@android:/ # rm /data/local.prop
23. root@android:/ # rm /data/local/tmp
24. root@android:/ # mv /data/local/tmp.bak /data/local/tmp
25. root@android:/ # exit
26. C:\ADB> adb reboot
but my android stuck at script
root@android:/ # rm /data/local/tmp suddenly my tab turn off...
i've forgotten that battry empty,it must chargered...

after 30 minutes, i try connect tab to laptop again..suddenly my laptop stuck and hang, and i must restart my laptop
after restart..adb shell appear alert "error: device not found" and blank screen
searching..googling...
and i've got the answer


enter cmd mode on pc, then
adb kill-server
adb start-server
adb devices

and continue my script...until finish "adb reboot"

source kaskus SFT community