Windows 8 build 7973 (fbl_grfx_dev1)

6.2.7973.0.fbl_grfx_dev1.110330-1700
Build of Windows 8
Screenshot
OS familyWindows NT
Version number6.2
Build number7973
Build revision0
Architecturex86, x64
Build labfbl_grfx_dev1
Compiled on2011-03-30
Expiration date
Timebomb2011-07-01 (+93 days)
About dialog
Windows8-6.2.7973-grfx-About.png

Windows 8 build 7973 (fbl_grfx_dev1) is a build of Windows 8, which was uploaded in both the x86 and x64 variants on 5 June 2022.

Editions and keys[edit | edit source]

Edition / SKU Key
Home Basic YGFVB-QTFXQ-3H233-PTWTJ-YRYRV
Home Premium RHPQ2-RMFJH-74XYM-BH4JX-XM76F
Professional HYF8J-CVRMY-CM74G-RPHKF-PW487
Ultimate D4F6K-QK3RD-TMVMJ-BBMRX-3MBMV

Redpill[edit | edit source]

The Redlock tool can be used to unlock all of the Redpill levels on this build, including the Start screen.

The Metro in this build is identical to its alternate compiles.

Bugs and quirks[edit | edit source]

Aero[edit | edit source]

This build appears to have a slightly broken Windows Aero theme, with only the top portion of the window frame using the blur effect, leaving the side borders transparent.

Upgrade[edit | edit source]

When upgrading to this build using the new Windows Setup tool, installation might fail. When the Applying computer settings phase starts, a runtime error will occur with C:\$WINDOWS.~BT\Sources\Install.exe, and alt-tabbing after clicking OK will reveal another error saying that Windows could not complete the installation. To install Windows on this computer, restart the installation. In order to upgrade to this build, use the older setup tool located in the sources folder or use Windows Setup files from a different build.

Advanced Vector Extensions CPU bug[edit | edit source]

This build's x86 compile will not boot on some CPUs with the Advanced Vector Extensions (AVX) instruction set due to a bug where a CPU triple fault occurs immediately after the boot screen is first displayed. A workaround is discussed later in the article.

General[edit | edit source]

If using VMware Workstation versions 15.x or above changes in build 7878, attempting to restart or shutdown in this build will cause a softlock. To fix this, use the Power menu from the VM section. This bug persists until build 8008.

Aero Glass in Starter and Home Basic[edit | edit source]

This build automatically enables Aero Glass transparency after installing the Starter and Home Basic SKUs, despite product policies limiting usage of such effects. Changing the current visual style over to a different one (e.g.: Windows Basic) will disable glass effects.

Compiler[edit | edit source]

This is one of the first builds to be produced using a new compiler. However, the problems surrounding it at that time resulted in the build becoming unbootable on certain hardware, as the boot loader does not properly function on modern x86 CPUs, namely Intel processors with the AVX instruction set and a select number of AMD CPUs. As a result, a CPU triple fault occurs resulting in either a crash on a hypervisor or a reboot on real hardware.

Patching winload.exe to run on Intel processors with AVX[edit | edit source]

In order to properly enable SSE instructions for machines using Intel processor with AVX, the 9th bit in Control Register 4 (CR4) must be turned on. The following code is executed and is located in winload.exe at offset A552:

mov     eax, cr4        ; 0f20e0
or      eax, 20h        ; 83c820        -- Turn on 5th bit, PAE (Physical Address Extension)
mov     cr4, eax        ; 0f22e0        -- Store it in CR4
mov     eax, cr0        ; 0f20c0
or      eax, 80000000h  ; 0d00000080    -- Enable paging
mov     cr0, eax        ; 0f22c0

By default the following bits are set in CR0: Protected Mode (PE) (0x00000001), Monitor co-processor (MP) (0x00000002) and Extension type (ET) (0x00000010), with no bits in CR4 set initially, so the need to turn on the 9th SSE bit (i.e. OR with 0x600) should be done, but due to limitation in this piece of code, a rewriting needs to be done and the following approach may be used instead:

mov     eax,620h        ; b820060000
mov     cr4,eax         ; 0f22e0
mov     eax,80000013h   ; b813000080
mov     cr0,eax         ; 0f22c0
nop                     ; 90
nop                     ; 90
nop                     ; 90
nop                     ; 90

As a disclaimer, patching winload.exe with these changes will invalidate signatures and thus requires {bootmgr} nointegritychecks to be enabled in the BCD in order to boot with the patched winload.exe, as well as ownership of the file in both %systemroot%\System32 and %systemroot%\System32\Boot need to be altered in case file replacement was not possible.

Compatibility[edit | edit source]

VMware Workstation[edit | edit source]

For another workaround on the Intel SSE bug that does not involve patching and disabling security checks, the compatibility level must be set to version 7.x or lower in order to boot this build. In addition, the following block of code must be added to the VMX (virtual machine configuration) file in order to allow this build to boot on modern Intel CPUs:

cpuid.0.ebx = "0110:1000:0111:0100:0111:0101:0100:0001"
cpuid.0.ecx = "0100:0100:0100:1101:0100:0001:0110:0011"
cpuid.0.edx = "0110:1001:0111:0100:0110:1110:0110:0101"
cpuid.1.eax = "0000:0000:0000:0001:0000:0110:0111:0001"

The above configuration is mostly not required if the host machine has an AMD processor, and as such only requires the compatibility version to be changed.

Gallery[edit | edit source]