Yes, you're not the only one. I have alienware 17 r4 and I'm experiencing the same problems.

Same issue here. Before rebooting, the update says 'update from 1.2.3 to 1.2.3', but this is the 1.2.4 update. How to fix this problem? All the games that I play now suffer from the lag issues when 1.2.3 is installed :(

I'm facing the same issue...

I have a 15/R3 and I'm having the same issue and did for the previous update as well. It's getting OLD and very tiresome.

Same here. I have a1 year old 17R4

My new 17 R4 bought on after-xmas sales just over 2 months ago came with 1.2.3 installed.  Fortunately I was able to follow the esc/ctrl roll-back instructions below and this ended up taking it back to 1.1.9.  I then updated this to 1.2.1.

1. shutdown your laptop.

2. unplug the power cable.

3. Hold down the ESC key and CTRL key.

4. Plug in the power cable whilst still holding the ESC and CTRL keys down.

5. Press the power on button.

6. When it starts to boot, fans etc come alive, release the ESC and CTRL keys.

7. It will boot to a bios page where you can select ROLL BACK BIOS

8. Press the arrow keys to select this option and press RETURN

9. Let the pc do its thing and it will eventually restart and when windows boots if you right click the widows key, click on run and type in dxdiag and hit return you will see what bios you are at and it should be back to 1.2.0 or 1.2.1.

You can now run support assist if you arent on 1.2.1 and update to the latest stable bios.

Going to 1.2.1 improved my Windows mixed reality VR performance significantly (~15% higher fps) and this worked great.  Then I got the notification from dell that 1.2.4 was available and that this was an Urgent update due to the new intel security features.  So I did this and now my performance is back down to where it was with 1.2.3.  

I tried the roll-back method I used before but this refused to allow me to roll-back.  I think that there is some security feature that stops this from happening.  Needless to say I am not very happy with all this and I can only hope that Dell provides me some way to get back to 1.2.1, but I kinda doubt that's going to happen.  Maybe future updates will improve this, ha-ha!

Dell after-sell service too bad, feedback this same issue to their service team and told them i found similar cases from online forum. They remote access my laptop15R3 to confirm the issue, tried reinstall 1.2.4 bios in Windows and manually in bios setup mode but both failure. And they said my might be my motherboard faulty then cause the bios cannot be install. But i told them i don't think it faulty because it working fine, and so similar cases in forum too, but they insist to change it. They sent a technician(from subcontracted company, unprofessional, disassembly laptop without wear anti-static wrist strap before start, like no experience disassembly Alienware before, always thinking for the next step)(recall back i regretted, i should show him first the video of disassembly from youtube) to replace my motherboard by a refurbish board but still failure, same cannot install 1.2.4 bios. **bleep**??? then will do disassembly my laptop again? cos i'm sure want put back my new board instead of refurbish board!!! So famous brand in world but have no such experience and treated my laptop as an experiment to testing? And next they wanna ask me to try is if able to roll-back the bios? o Dear guys, do not let them disassembly your laptop if you want keep your laptop in new condition, unless they can guarantee it work.  

Same problem here, drop on fps on high end games after some time playing.

This BIOS issue can be on purpouse for forcing us to upgrade, specially if they can't take us back to the sweet spot but I hope there's an upgrade where all this can be fix, cause also is difficult to optimize bios for certains models all the time.

I was installing the BIOS update on my DELL R4, but I never rebooted and my screen went black and unanswered, apparently the update did not end, does anyone know of any solution?