I think that the wiki of Sakaki is very good.
If you have an external way to flash the firmware then you are quite safe,
unless you make mistake on the connection. But it is quite difficult.
I reflashed the firmware many many times with incremental changes and I had
always a backup ready. One of the flash end up also in a brick but flashing
back the prior version solved the problem.
For the x230 you can even flash coreboot (lucky you)
https://www.coreboot.org/Board:lenovo/x230
It is written that the only way to flash the ME is externally.
You can use this guide as well:
https://github.com/corna/me_cleaner/wiki/External-flashing
I think you could get a pretty close to freedom laptop even more than I
achieved.
