I found a way to downgrade
Disclaimer:
By doing so you could easly
brick your reader, this method worked one time for me, so if you don't understand fully what you are doing, please refrain from using it.
I don't know if user data affected by flashing, but do all possible backups in advance.
Method was used to downgrade firmware from 3.1 (if I remember correctly) to 2.1, but should be fine for any version, test required though.
Needless to say your reader should be fully charged.
1. You need to find old version of the firmware for your reader. Check the waybackmachine.
2. Extract the firmware with
this tool
3. Follow
this instruction to extract system.img from system.new.dat.br
4. Apply the same steps for the vendor.new.dat.br to get vendor.img
5. Download and unzip
SDK Platform Tools
6. Copy all *.img files from update.zip (result of 2nd step) to platform-tools folder (from previous step)
7. Copy system.img and vendor.img to platform-tools folder.
8. Connect Nova 2 to PC via usb. Turn your Nova 2 on while Hold back button until you see recovery menu.
9. Use back button to navigate. Hold back button to select "Reboot to bootloader". You will see "Rebooting to bootloader..."
10. Now navigate to platform-tools folder and start CMD there.
11. Type in
to check that your reader is presented.
12. One by one issue this commands in exact order.
Code:
fastboot flash system system.img
fastboot flash vendor vendor.img
fastboot flash boot boot.img
fastboot flash rpm rpm.mbn
fastboot flash rpmbak rpm.mbn
fastboot flash aboot emmc_appsboot.mbn
fastboot flash sbl1.mbn sbl1
fastboot flash sbl1.mbn sbl1bak
fastboot flash splash.img splash
fastboot flash recovery.img recovery
If there is errors, don't worry, I guess. There is no patrition splash for example, I do it only because this write-in operation presented in META-INF\com\google\android\updater-script.
13. And finally:
Feel free to ask any question regard the proccess. Do all flash operation with extreme caution, there could be no way back.