I have successfully upgraded my HP 15-ef2126wm display to the BOE NV156FHM-NY1 (Matte 15.6" 1080p IPS 144Hz G-Sync, 1200:1 CR, 71% NTSC). Notebookreview forum members may remember the various threads about the NV156FHM-N4B; for all intents and purposes the N4B and NY1 are the same panels just in different mounting form factors, with the N4B having corner mounting brackets. The fit was perfect and the eDP cable connected fine.
Some key notes:
1. The NY1 does not have the black screen problem for full screen saturated colors that my N4B had when installed in my HP 15-bs234wm. This is probably dependent on the laptop model and or cable used.
2. The brightness controls started working after a firmware update from Windows update. I wasn't sure which update it was since it happened automatically, but I assume it can also be found on HP's website.
3. Contrast ratio is similar to the N4B but differences in panel uniformity make my NY1 look slightly worse on the edges. It may improve over time, but even if it doesn't, it's still quite respectable. Color accuracy is not perfect out of the box, but decent enough, so you will likely want to make or use an ICC profile.
Other notes: the NY1 display does not expose 60Hz mode, only 144Hz mode, which does of course work fine. It may be possible to edit in 60Hz mode but I don't really know how. The N4B does expose 60Hz mode in comparison. Input lag feels similar between both models. The color leaned too green out of the box and all I needed to do to fix it was reduce the green slider with the Windows color calibrator and create a new ICC profile. The gamma curve isn't quite perfect for sRGB, but I decided to keep gamma at stock since it's still close enough and is good for dark environments. The ICC profile I use is attached to this post (ICC profile location is C:\Windows\System32\spool\drivers\color).
HOW TO RESEARCH PANELS: use panelook.com and use the advanced search to choose the criteria you want for your display upgrade. The pin count (30 or 40), pinout and voltage requirements do matter, but voltage requirements do not need to be exactly the same as your existing panel, just close. I have read of a user upgrading a laptop display that had different enough voltage requirements that it fried his motherboard, but it's possible that was just due to a pinout incompatibility. The voltages and pinout can be found in display datasheets, so try to find the datasheet that matches your display and the one you want to upgrade to and compare. The main pin that you should pay attention to is the PWM pin, as its position can change depending on the display model. Most other pins will be the same and/or be named slightly differently but still be compatible. The connector SKUs on panelook may be slightly different but as far as I can tell, any 30-pin eDP cable will work with any 30-pin eDP display with the same connector pin pitch. It's mainly when the connector's pin pitch is different where there will be a physical incompatibility.
Once you've found the display model you want, you can find displays for sale on aliexpress or ebay. Make sure the listing does not say "compatible / for" and that the actual product name is on the sticker on the image in the listing, otherwise you could easily be buying something you don't expect.
You can find the NV156FHM-NY1 for around $100 on aliexpress and more expensive on ebay.
ICC profile:
NV156FHM-NY1-green_correction-stock_gamma.icc
There are a few characteristics of a PWM signal from high to low like voltage, frequency and duty ratio. However, which of these characteristics are controlled by the motherboard? Is there a handshake that let's the display choose what it wants, or does the motherboard firmware force one set of values regardless of which display is installed? So for example, does the motherboard only control voltage level and the display handles the rest, or does the motherboard also control the frequency of the signal?