As long as you can prove your intent was to work for the firm when applying to gc
I heard it is advised to stay for 6 months to avoid any unnecessary questions.
+1
First hand experience! I changed employer after 3 months of getting the GC. When it was time to have my citizenship interview 7 years later, the IO was definitely puzzled and kept asking me “wait, you changed employer 3 months after your green card?!”. The funny thing was that I changed employer and joined the startup started by my former manager who sponsored me the green card at the other company, so I made him write and sign a letter saying that I kept working for him and did the same tasks as before, and brought it with me at the interview. The IO definitely wanted to see that letter and actually kept the original copy in my file! I was so happy to have been overly cautious! My boss kept saying I was just paranoid. Based on my experience, I would then not recommend changing employer too quickly, it definitely got tense when the IO asked how long did I stay with the petitioning company, and his face changed visibly after I said “about three months”.
You got away, bro. Only paranoid survive (c) Andy grove
A year
Congratulations. You can change job the next day. No problems with neutralization in the future.