thx...a bit of help...i just downloaded Oma_RK31_Chuwi_V88_KK_4.4.2_v2.2_gen1 loader and Oma RK31 KK v2.1 Format NAND
i have this instructions
1. connect your Chuwi V88 to the power supply and to the PC via USB cable
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first install only
2. boot your Chuwi V88 and set storage mode to MTP and debugging to USB
3. run DriverInstaller.exe
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4. run RKAndroidTool.exe with admin rights
5. press power button and volume up button and hold for 12 sec
6. release the power button
7. release volume up button when "Found ..." is shown
8. select EraseIDB
9. select Run
10. V88 will boot into CWM
11. run format_NAND fix (install zip from ext_sdcard)
12. select full format
13. go back, reboot system (do not fix su)
14. wait 4 min