Same here, it seems to be a Mi2s problem. Different front camera model maybe.I have a MI2S-32GB.
The main camera is working very well, only the front camera is not working.
For the carrier name, this rom (like many others) takes it from a closed source library made by qcom.
The name of my operator had an error and M1cha has been so kind to fix it (by hex-editing this lib).
If in your case it shows only numbers, I guess your operator was not foreseen by qcom at the time they built their lib... :-(
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