Troubleshooting 4-7Bootblock Recovery Code Checkpoints 0The Bootblock recovery code gets control when the BIOS determines that a BIOS recoveryneeds to occur because the user has forced the update or the BIOS checksum is corrupt. Thefollowing table describes the type of checkpoints that may occur during the Bootblockrecovery portion of the BIOS.NOTE:NOTE:Checkpoints may differ between different platforms based on system configuration.Checkpoints may change due to vendor requirements, system chipset or option ROMsfrom add-in PCI devicesD5 Bootblock code is copied from ROM to lower system memory and controlis given to it. BIOS now executes out of RAM. Copies compressed bootblock code to memory in right segments. Copies BIOS from ROM to RAMfor faster access. Performs main BIOS checksum and updates recoverystatus accordingly.D6 Both key sequence and OEM specific method is checked to determine ifBIOSrecovery is forced. Main BIOS checksum is tested. If BIOSrecovery is necessary,control flows to checkpoint E0. See BootblockRecovery Code Checkpoints sectionfor more information.D7 Restore CPUID value back into register. The Bootblock-Runtimeinterface module is moved to system memory and control is given to it.Determine whether to execute serial flash.D8 The Runtime module is uncompressed into memory. CPUID informationis stored in memory.D9 Store the Uncompressed pointer for future use in PMM. Copying MainBIOS into memory. Leaves all RAM below 1MB Read-Write includingE000 and F000 shadow areas but closing SMRAM.DA Restore CPUID value back into register. Give control to BIOS POST(ExecutePOSTKernel).See POST Code Checkpoints section of documentfor more information.DC System is waking from ACPI S3 state.E1-E8 ECEE OEM memory detection/configuration error. This range is reserved forchipset vendors & system manufacturers. The error associated with thisvalue may be different from one platform to the next.Table 4-2.Checkpoint Description
