Hello,
i have trouble with my avic-f860bt
When boot and after few times with saying 'reading....", i have a error message "update failed"
I try different usb key with different version firmware (1.08 1.115, 1.21), the same thing happen
i can see at one moment, beforce this screen, an another screen who say "Version 1.15 => 1.21" and one line at the top : "0%" and after "-1%"
When it was at 1.08 version, i could enter test mode avec check the sdcard with success. i backup card and change mode to read with my pc ans upgrade with win32diskimager
The sdcard seem to be ok.
I dont know what can i do now 
Can you help me ?
Thank you
Emmanuel