How to delete obsolete OEM partition and update difficult BIOS

Thanks once more to everyone who helped me successfully transition my ASUS notebook and then ASUS Core i5 desktop to W10. This dual core ASUS P5G41T desktop was the next to make the successful swap to W10 (by upgrade, with most of the drivers intact), but now a couple of blank screens and frequent crashes when using the PC has made me decide to change the 12yr+ Seagate hard drive to a new Sandisk SSD before the drive expires on me. Several DISM/Scanhealth scans show there are no corrupt files.

The problem is an 8GB OEM recovery partition which came with the then Packard Bell Vista PC, because when I replaced the MOBO and had the OS changed to W7 (OEM upgrade), I asked the store technician to remove the OEM recovery partition, but after taking advice, he said it could not be done, and I later read online that OEM recovery partitions are EFI protected. Since then, I have changed everything on the PC i.e. new PSU, new graphics card, new cpu fan and case fans, new CD drive and even a new PC case, so only the processor and hard drive are original.

Since the BIOS is ‘SATA AHCI not supported’, initially I wasn’t sure that I could upgrade to SSD, but ASUS has released a BIOS update 1101 (27/06/2012) for this MOBO which may have AHCI settings, and has also released a ‘New SSD’ list. However, no matter how many times I try, either by flash drive or CD disc, I have been unable to flash the new BIOS using the EZ Flash Utility, because the BIOS.ROM update file itself does not show up on-screen. The flash drive shows up as drive A.

How do I flash this BIOS? Or, is there a workaround to bypass the AHCI not supported settings?

Also, would it be possible to delete the obsolete OEM partition and migrate the just the upgraded W10 OS together with my settings to the SSD e.g. using Macrium Reflect or Mini Tool Partition Wizard?

Specs: ASUS P5G41-T-M LX with SATA 3GB/s; current BIOS 1001 (08/10/2011); CPU Intel Dual Core E2160; PSU Corsair 450W; Graphics Card Nvidia GeForce GT 610, Hard Drive Seagate 160GB. Windows Version number 1909 Build 18363.657.

Use MiniTool Partition Wizard to delete the OEM recovery partition and add the space to C: drive.

Have you tried Winflash to update the BIOS?

Update BIOS - How to use Winflash to update the BIOS version in Windows system? | Official Support | ASUS Global

Thanks guys. I'll post an update asap.

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@NavyLCDR, the OEM partition deleted successfully with Minitool PW, and is now 8GB unallocated space. Disk Management also now shows C drive 140GB and System Reserved 100MB. Does this mean that if I’m able to, I can now migrate the OS successfully to the SSD without the 8GB unallocated disk space? There doesn’t seem to be any option to delete the space itself.

@Cr00zng, Winflash would not run unless I installed the ATK driver, so I did then it said it could not flash the BIOS file. I had another look at the EZ Flash utility page and saw that I was able to navigate through the C drive, so I went to the desktop and clicked on the new 1101 BIOS.ROM file, and got the magic question. With the BIOS now successfully updated, I ran HWINFO to check for BIOS changes, but it still says “SATA AHCI not supported” and “UEFI BIOS not capable”, and the SATA Controller still says “Device Class – IDE Controller”.

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Since the questions I asked have been answered successfully i.e. how to delete OEM partition and update BIOS, I will now close this thread. I still need advice with data migration to SSD so I'll open another thread specifically for that. Thank you NavyLCDR and Cr00zng.