Hello community! 
I did a big mistake and I ask you friendly for help.
I flashed my MSI X370 Gaming Pro Carbon BIOS from the lastest version (1NV) to an older version (1L0) via USB MSI EFI Flash Tool. All went good but my system is not starting anymore. All fans and rgb lights are on. All Debug lights are off.
After reading through some threads, now I know I was not able to rollback and got stuck.
The latest (1NV) BIOS had an update for the SMU Firmware and now there is a conflict between the BIOS and SMU Firmware.
I’ve ordered a CH341A programmer with 1.8 volt adapter (cables and connectors will arrive tomorrow/saturday) and I want to backup the whole chip and flash the latest BIOS again.
But when I do a clean flash with the stock BIOS I’ll lose all specific informations like MAC Adress, Serialnumber,… .
Now I’d like to ask you guys for help.
How can I add my MAC Adress and all other specific informations into the new clean BIOS version? Or is there another way to fix my BIOS?
Many thanks in advance! 
Pundy
Update:
I was able to read the chip with the ch341a programmer. I’ve made a couple backups and uploaded them with the latest BIOS version. I’ve made pictures of the MAC and SN Stickers on the board (I’ll send them and backup bios separately via pm).
Once again I’ll be very thankful if someone can fix the BIOS with all specific infos.
Thank you!
Resolved in PM 