Laptop boots correctly once if new RAM installed, beeps on next restarts.

[Mihailo2]

Good day.

Laptop: HP Probook 450 G5. (CPU i5-8250U)

Original RAM:  1x MICRON 8GB 2666MHz PC4-21300 (MTA8ATF1G64HZ-2G6H1)

New RAM: 2x KINGSTON 16GB 2666MHZ CL15 (KF426S15IB1/16)

BIOS ver:  Q85 01.24.00 (latest one)

Documentation states that maximum supported RAM: 2x16GB at 2400MHz

After changing RAM to one or both of the new sticks laptop boots fine once (showing usual warning that ram size changed). At that time all works great, ram tests pass successfully and no problem with running benchmarks on main OS. But after reload (or power off/on) BIOS won't boot up beeping 3 times (supposedly RAM problem). Then if I install original 8GB stick it will boot up fine (again, showing message about changing ram size first time) and will work fine afterwards, even after more restarts.

Replacing original stick with new ones again allows another single successful boot, and beeping BIOS failures on reloads after successful one. Waiting between reloads doesn't change anything, not loading into main OS either. As soon as BIOS loads successfully for the first time, all consecutive loads fail.

At the same time if any new stick used as secondary to original 8GB one, everything works fine and all ~24GB are available.

Found the same problem being described on superuser.com but no resolution:

https://superuser.com/questions/1549252/ram-upgrade-laptop-wont-boot-after-restart-works-on-initial-...

He has different HP Laptop and RAM but otherwise problem sounds exactly like mine.

Would be very thankful for any info on possible solutions or even if it's simply known incompatibility that can't be resolved.

I would've just tried to look for another memory, but consistently successful initial boot makes me think that it's BIOS bug and any other unoriginal sticks wold cause the same problems.

BIOS Reset (windows+B) was tried, no effect.