cle2000 customized ujb V1.1 (automatic undo jailbreak written by Liwil) which allows to revert to the Official stock FW of your region.
All credits to Liwil.

Here are the required files (/mnt/sda1) :
- UDP20X.bin or UDP20XRU.bin or UDP20XEU.bin or UDP20XAU.bin or UDP20XCN.bin or UDP20XJP.bin or UDP20XTW.bin => official stock 65-0131 FW of your region
- bdpprog_us or bdpprog_ru or bdpprog_eu or bdpprog_au or bdpprog_cn or bdpprog_jp or bdpprog_tw => official stock 65-0131 "bdpprog" of your region renamed with the appropriate suffix (be careful : has to be valid, otherwise : brick !)

If all prerequisite files are present, a reboot will be done to use the official bdpprog, and then the Official stock FW will be installed. For
your specific JB files present in /mnt/ubi_boot (as Overlay for example) will be kept even after the reverting to Original stock firmware. They will be retrieved if you decide to jailbreak again.

IMPORTANT : wait for the opening of the tray (which means the end of the process) before unplugging the USB flash drive!

IMPORTANT 2 : if you put a bdpprog with a suffix different than its region or if the official firmware is not the correct one, the firmware upgrade will fail and your Oppo will shutdown in order to get back to JB.

A log is generated on the USB flash drive (/mnt/sda1) : revert_stock_ujb.log

WARNING : if you leave the USB flash drive plugged into the Oppo and had previously already ran succesfully the ujb_stk_bdpprog AutoScript followed by the jb_stk_bdpprog AutoScript, I added a security check to avoid the 2nd launching of ujb_stk_bdpprog.
This is logged and if you want to launch it again anyway, you just have to remove the log in the USB flash drive.

Do not forget to do a factory reset after the firmware upgrade.