Hi!
I would like to have the following features.
1. Unlocked Advance Menu
2. Additional CPU Microcode
3. If possible NVMe support
BIOS and Updated MicroCode Link: https://mega.nz/file/Pxo0iRhR#wlcynF0vAs…GTFU3rvdnfofszc
There is no necessary to add another cpu microcode since everything that motherboard need is packed up in microcode 306C3, and it’s already the latest one. Try this file i attached.
mod.rar (8.38 MB)
Thank You for the mod!
Unfortunately I think I mess up the dump.
both the moded and original dump can’t boot the system with DGPU.
I guess I’ve have to reflash original BIOS and dump again!
Sorry for the trouble
Hello Koekieezz! Thank you sooo much for sharing this mod BIOS as it’s precisely what I was looking for!
I tried to flash it by DOS utility “DOSFlash.exe” provided by HP for HP ProDesk 400 G2, it seems correctly writing the .bin, but just after writing it reports the error “invalid system BIOS” (I suppose being this mod BIOS not HP signed) and the bios unfortunately does not appear updated.
Please could you suggest me what tool to use to successfully write this mod BIOS (maybe Intel FPT or another)?
Thanks again for your help!
You could only do with programmer afaik
thanks a lot for the crucial tip: the very popular “CH341A” will reach me soon and I’m going to try flashing the mod BIOS directly, then I mean to report here the happy ending! 
You should dump your own bios rather than flashing the bios posted here.
Exactly! Indeed I’m going to backup the current original HP BIOS first (that’s precisely the same version of the mod one: 00.02.56 Rev.A), then I’ll do my best to flash yours: is there a particular programming software you could suggest me? (I am considering to use this one https://www.instructables.com/CH341A-Programmer/ )
I usually use neoprogrammer for ch341a, just make sure the usual ch341a driver is installed after you plug the device in your pc/laptop.
before clamping the soic8 clip (if the biosc chip is soldered, not on dip8 package), take off the cmos battery and make sure it is not connected to power source, just making sure that the motherboard wont receive any power, then you could clamp the chip to the clip.
Thank you very very much Koekieezz, you were precious once again: I planned to unplug the power supply from the MB but I wouldn’t have thought about CMOS battery, really good idea!
I confirm the chip (MX25L6405D) is soldered to the MB so I plan to use the clip (my first experience with it), I will install the most recent driver by WCH “CH341PAR.EXE” (USB to JTAG/SPI/I2C/Parallel/GPIO interfaces one-key installation driver for Windows) ver. 2.5 from CH341PAR.EXE - NanjingQinhengMicroelectronics then I am going to launch “Ch341a Neo Programmer V2.2.0.10” from GitHub - ny4rlk0/BIOS_FLASHER_ARCHIEVE 100% following your suggestions 
I am 100% hopeful now!
Here’s me again for the full outcome: first I patched the CH341B (I got that sold as CH341A! 
) to drive all the data lines 0/3.3V (than 0/5V), then I unplugged the CMOS battery, the power supply, CPU and RAM from the MB; the clip worked perfectly since the very beginning BUT the motherboard itself appeared absorbing almost 2 Ampere just on the 3.3V branch turning the poor CH341B completely off with its small 3.3V regulator: at that point I plugged my bench power supply and provided all the Ampere the 3.3V branch asked on the MB, the CH341B promptly turned back on, it was perfectly seen and driven by the software, but the flash chip did not respond at all. 
At that point (a bit discouraged) I unplugged my bench power supply, and I just plugged the original power supply back (still leaving CPU/RAM/CMOS battery apart) therefore powering all the MB power branches at the same time (3.3V, 12V, etc.) and… THE 1ST LITTLE MIRACLE HAPPENED! 
The flash chip immediately and perfectly began responding, so I dumped the original BIOS 3 times collecting 3 perfect copies.
Finally I could flash Koekieezz’s glorious MOD-BIOS: again succeeded 100%
But the last unexpected issue promptly arrived… 
I turned everything off, I reinstalled everything (CPU, RAM, Battery, fan and Sata cables, etc.), then powering the PC (G2 HP ProDesk 400) back on, the system began going in an infinite reboot-loop…
I tried to completely unplug the 220V line, waiting minutes, then plugging back, the system immediately resumed its loops: I felt again pretty discouraged and I was going to flash the original BIOS back (how my poor MB cannot afford a smarter BIOS?), but first I realized to try the only thing I had to do: to turn the system OFF whatever it takes (this poor PC hasn’t a reset button, it has 1 only terrible “soft power button” that is meant to work -I suppose- also as a reset button): keeping the power button pressed long, and after about 4-5 failures (the reboot loops simply ignored the soft power button state) the system finally turned OFF! THE 2ND LITTLE MIRACLE HAPPENED!! 
At that point, the system simply could turn on NORMALLY and WORKED PERFECTLY with its brand new BIOS!! I could successfully install an M2 boot drive (by a PCIe adapter) and it launched immediately: FINAL RESULT REACHED!!
I am really really glad and grateful for that, I wished to report all of my experience in detail in case it may be helpful to others, once more I need to thank Koekieezz for such precious BIOS!! 
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did any additional/hidden advanced menu shows up or just as is? afaik the bios i posted above shouldn’t be used at all since the owner of the bios said “dump is messed”, also nice discovery on how to dump your bios, probably you should make a guide for it.