laptop RAM issue

[vladNMP]

hi, currently I am waiting for my HP Omen 17-an0xx (17.3 1080p 120hz, 7700hq, 1070, 8RAM, 256ssd, 1tb hdd) laptop to arrive, and it has only 1 RAM stick of 8gb ddr4 2400mhz 

i currently have a Lenovo IdeaPad Y700-15ISK which has inside a 8gb ddr4 2133mhz. there are 2 topics of discussion:

1. can i put lenovo's RAM stick inside HP? is there any significant drawbacks? i mean i read on the internet that there are chances to work or not, but if it does it will limit the 2400 to run at 2133. if it doesn't, it might show a "memory failure error", is that dangerous to the laptop itself?

2. as far as I read about the retailer, people lost their warranties because of upgrading their laptops. official HP support says it's Ok as long as you dont damage anything. can the retailer add extra warranty stickers or glue inside? it sounds really stupid but I dont see any other way they can tell you actually upgraded the ram/hdd/ssd (10 screws to open the back as internet shows)

[genexis_x]

1. It will probably work, but both RAM will run at 2133MHz spec

2. Warranty will not be voided unless you damaged anything. Sticker doesn't matter. Glue only used by anti-consumer products like Macbook and Surface