It will not work hc25 is not the same as hc28 I have currently made that mistake or someone else made it (as I dont remember who changed this memory chip on this card or i bought it like that can't remember anymore), as I currently have a gtx980ti with both hc25 and hc28 that won't start, even though memory power rail is up and running and the gpu core voltage is present. The mats test for this card failed with strange errors when i tested it something like 32 bits is different than 8.
So my recommendation based on evidence, buy a "hc28" chip.
and NO it won't break the GPU as both have the same ball out scheme but the data side is different
have a look
https://photos.app.goo.gl/2wWttRSd4MdVUs3M9
One more thing, both HC25 and HC28 actually have the same size the only noticeable difference from the specs according to samsung is the 8Gbs vs 7Gbs data rate speed. Which could also require some different memory clock rates as both have different data rates.
in theory the HC28 7Gbs is replaceable by HC25 8Gbs but not the other way,. But in practice it seems not.
Actually even in theory it won't work, if I get this right, the memory clock is tightly coupled with the data rate speed of the chip.