Hello guys, recently found this forum and enjoying it a lot - so much info and things I didn’t know!
I am facing an interesting task - given no budget, a subject mobo running the latest official BIOS (7.30) and Kaby Lake Pentium G4620 (yeah, those still do exist!) with a microcode of 906E9, I intend to upgrade it with an ES QHQG L501C (506E1, stepping Q0) - and if it works at all, try to overclock it.
After reading the guides here I realized that I need to mod a BIOS to contain both microcodes at the same time as there doesn’t seem to be such stock or modified ones. Latest Korean one for this mobo (v1.90) only contains microcodes up to 506E3 (Skylake) and stock ones do not have support for ES chips neither the BCLK OC functionality which was removed in version 2.90 and onwards.
I have got a Ch341 programmer and a couple of Winbond chips so reflashing should be easy, also one chip that’s currently in the board is planned to stay with a default firmware and settings for easy rollback if (when) it all goes wrong 
I’m wondering which BIOS to start with - Korean one seems the most obvious candidate as it’s flash and plug the CPU. I’m somehow limited by the time I can spend on this machine though, as it’s in operation the whole day so I just have a few hours in the evening. That makes me want to have 2-in-1 BIOS so that the rollback to Kaby Lake shouldn’t take too long.
I tried to play with UBU and didn’t manage to find an easy way to completely remove 2 unused microcodes (for Skylake A0 and 506E3) and add 906E9 while I understand the logic that I might locate the files for the newer versions of both in UBU folders and substitute them with a necessary microcode .bin just renaming it to the original filename so that UBU would think it’s upgrading the existing microcode but in fact it will replace it with Kaby one.
I’m also somewhat concerned with a release date of that Korean BIOS as it dates back to mid-2016 and there were at least 5 official releases since then, all adding something to overall BIOS functionality and/or compatibility:
01.90 - 24.09.2015 - Improve RAM compatibility and boot time ← that’s what Koream BIOS is based on
02.10 - 28.10.2015 - Support DDR4 OC, Improve boot time, Improve DRAM module compatibility, Improve PCIe compatibility, Update ME
02.20 - 24.11.2015 - Improve Windows 10 boot sequence, Update NVMe Configuration, EZ Mode module and Microcode; Improve memory, PCIe compatibility
02.40 - 20.01.2016 - Update Nick’s XMP table (whatever it means), Update Microcode, Capable of enhancing CPU performance.
02.50 - 26.01.2016 - Update microcode to 0x74, Improve DRAM compatibility.
02.60 - 19.02.2016 - Update EZ mode, Improve DRAM compatibility, Add CPU_Fan1 type item in BIOS.
02.90 - 15.03.2016 - Update microcode to 0x76, Remove Sky OC function ← no go for me 
03.10 - 28.04.2016 - Modify CPU fan behavior, Improve DARM compatibility, Support 4k native HDD, Update NTFS module ← (could it be of some interest for me?)
(marked in bold are the areas that I am worried about, won’t it lead to OS crashing/not booting at all due to NVMe m.2 Samsung 970 SSD?)
So many questions, please forgive me for the long post and being risk averse - previously I was just updating the BIOS to the latest stock one and forgetting about it so it’s a lot of an exercise for the first time.
Right now my action plan is:
- To add Kaby microcode to Korean BIOS (and possibly update AHCI/ME/other drivers that UBU might suggest); ← here your help is highly appreciated to avoid all manual work with UEFITools and FIT tables that scare me
- Flash that BIOS to a second chip, plug and run it not even touching the current CPU to make sure the whole system boots and is stable (especially the storage subsystem);
- If that step passes, go for a removal of CPU cooler tower, thermal grease and all of that work, install ES CPU and give it a try;
- If it works, the job is done, I’ll proceed with BIOS settings tweaking, if not - I’ll revert to the stock CPU and BIOS.
If I’m planning something completely wrong, or there’s less intrusive and work-intensive way - I’m all eyes and ears to hear the community wisdom 
@DriVE654 Hi, there are some problems with attempting to do what you request.
1. Only BIOS v2.23 is “Capable of enhancing CPU performance” AKA Sky OC.
2. All BIOS below v7.00 (i.e. v1.x to v3.x) don’t support Kabylake as they have ME FW 11.0.xxxx (you need 11.6.x), they also have no Kabylake ACPI support (and of course no Kabylake microcode).
3. All BIOS below v3.20 have VBIOS OROM v9.0.1024 (or earlier) with GOP VBT v1.97 and GOP UEFI driver v9.0.1029 (or earlier) - you need to have at least VBIOS OROM v9.0.1034 and GOP VBT v2.00 with GOP UEFI driver 9.0.1037 for the Kabylake iGPU to function.
I would suggest using BIOS v7.10 as it has support for both CPU’s or editing BIOS v7.30 with CoffeeTime to add the microcode for CPUID 506E1 back in (and your MAC address at the same time so it does not get erased) and then use UBU to update any other modules afterwards.
You may also want to remove the flash descriptor lock using CoffeeTime.
chinobino, wow, thanks for the info, I didn’t consider it all!
It changes the plan significantly - actually I don’t have a plan to keep running that Kaby Lake, instead I’d prefer to put that ES CPU along with its BIOS and forget about it.
I will see when I can flash the Korean BIOS without any modifications and do the CPU swap.
Edit: on the other hand, do you think it’s worth making a full coffee mod and sell both old CPU’s in favor of one i5 9xxx?
Many thanks!
@DriVE654 If you don’t need to be able to swap CPU then you can pick any BIOS except v7.30, if you prefer the Korean v1.90 and you have a spare BIOS chip then go for it.
You should be ok with an i5 9xxx chip on that board, the VRM uses the Intersil ISL95824 controller and has 4x2 power phases for the CPU which should handle a 9600K but you wouldn’t be able to overclock it.
Hello again, I have tried this ES CPU on a Korean BIOS and… it doesn’t start at all 
it’s a pity but at least I have one problem less and don’t need to deal with it anymore.
Next idea is to fit some CoffeeLake instead as it seems better and somewhat easier way to get the most out of this motherboard.
Shall I open a new topic or can rename this one and keep posting here?
Many thanks!
@DriVE654 Hi, personally I would start a new thread in the BIOS Modding Requests but it’s up to you really.
Either way make sure to make a complete back up your current BIOS chip either using Intel’s FPT or a programmer (so you don’t lose your MAC address etc) and also provide a link to the official ASRock BIOS you want to mod.