EPYC 3rd Gen, Resizable BAR support

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biela

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Jan 20, 2024
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Ah OK I see how you're doing it now, thanks! Do you select the entire region above the trailing header to calculate the checksum? I'm using ImHex and I'm struggling to find a way to calculate the correct checksum (just trying use the vanilla RBU file for now)
 
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biela

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Jan 20, 2024
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Yeah all good now, it looks like ImHex wasn't calculating the correct checksum. I've got proper rebar support on my MZ32-AR0 with EPYC Milan now and using the latest BIOS. Thanks!
 
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derecskey

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Feb 28, 2025
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Usernae said:
Success, now my a380 works well with the latest driver on mz32-ar0.

github.com

List of working motherboards · Issue #11 · xCuri0/ReBarUEFI

Motherboards which don't support at least 2GB BAR size are considered not working. If you're having any issues please see Common issues (and fixes) before replying. Use this format in your comment:...
github.com github.com
Click to expand...
Greetings. I recently went through the modding process and added ReBarDxe.ffs to my MZ31-AR0 Rev1.1 board's R40 bios
  • Find 16M.RBU, open in HxD, strip off checksum footer (last 16 bytes starting at offset 0x10000000), save as 16M-ReBar.ROM
  • Open 16M-ReBar.ROM in UEFITool, search for Guid 3C1DE39F-D207-408A-AACC-731CFB7F1DD7, scroll down to bottom of section, Insert After, choose ReBarDxe.ffs, Save 16M-ReBar.ROM
  • Open 16M-ReBar.ROM in HxD again, Analysis -> Checksums -> Checksum-16, re-add Checksum Footer from original RBU (or manually enter, such that starting values are #GBT#ROM), replacing bytes 08 and 09 with the value calculated by Analysis-Checksums-Checksum16. Save as 16M-ReBar.RBU
  • Open BMC web interface, login as admin. Power Down system. Navigate to Maintenance -> Firmware Update. Choose 16M-ReBar.RBU, Start. Select BIOS in dropdown, then Proceed. Successful flash. BMC closes. Wait a few minutes. Log back in to BMC. Power -> Power On.
  • <Del> to enter Bios. Everything looks good. But here's my question...
After adding ReBarDxe.ffs, isn't it just the OPTION to enable ResizableBar? But ResizableBar isn't Enabled yet? Where in the Gigabyte bios can I find this option? I've had no luck so far, and booting into my OS and running GPU-Z I see that ResizableBar is Disabled.

Thanks in advance.
 
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RolloZ170

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Apr 24, 2016
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derecskey said:
After adding ReBarDxe.ffs, isn't it just the OPTION to enable ResizableBar? But ResizableBar isn't Enabled yet? Where in the Gigabyte bios can I find this option? I've had no luck so far, and booting into my OS and running GPU-Z I see that ResizableBar is Disabled.
Click to expand...
this doesn't add a BIOS option. you have to run an executable ReBarState to configure your GPU.
 
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derecskey

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Feb 28, 2025
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RolloZ170 said:
this doesn't add a BIOS option. you have to run an executable ReBarState to configure your GPU.
Click to expand...
You sir, are a genius. That, or you're simply better at RTFM than I am. I read through all of that, but have bounced around quite a bit between updating my BMC, using a Rev 2 bios ROM on a Rev 1.1 motherboard, hacking said BIOS, fighting over and over again with Intel Arc graphics drivers on both Windows and Linux machines. A lot of juggling in the late hours and I just needed to find that tiny one-liner in the docs about ReBarState.

You have my appreciation.
 
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RolloZ170

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