Help reflashing wiped EEPROM after bad flash

Discussion in 'BIOS Mods' started by HP_ENVY_User_32, Nov 2, 2021.

  1. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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    Hello all,

    I recently flashed a custom BIOS for my HP 6730B provided by Maxinator from BIOS-MODS.com in an attempt to enable dual-IDA mode to increase my CPU clock, however apparently this BIOS was untested ended up bricking my laptop so now I need help restoring it, and I haven't gotten any help from that website.

    I initially tried creating a USB recovery drive but the laptop would not initialize BIOS recovery.

    Next I tried using the Win+B and Win+V commands, but neither brought up the BIOS recovery utility.

    Next I decided to see what I could do with my CH341A, so I disassembled the laptop and hooked up the chip to a separate laptop. Upon reading the chip with ASProgrammer, I was able to confirm that the custom BIOS provided to me was flashed correctly by comparing the BIOS file to what was in the custom bios sent to me.

    I next tried to wipe and flash the EEPROM with the original BIOS, however it appears that the EEPROM is stuck in Write Disable Mode, so although I was able to erase the custom BIOS, I cannot reflash the original BIOS. Using "Unprotect" in ASProgrammer does not unprotect the chip. Checking the status registers for my EEPROM (SST25VF016B) confirms that WREN (Write Enable) is low (0) and writing is disabled.

    According to the datasheet for this EEPROM, Writing can be enabled by sending the hex code 06 to the IC, however it's not described how to send this code in the datasheet. Does anyone know how to re-enable write mode on this EEPROM?

    I have a few of these laptops, so I tried this BIOS again on another one, this time I removed the CMOS battery beforehand, and still bricked, I'm not sure what else to do here, it doesn't seem like there is any way to reliably purchase another one of these EEPROMS to replace the current ones.

    Any help is greatly appreciated!
     
  2. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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  3. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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    Need 3 more posts
     
  4. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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    To be able to...
     
  5. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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    Add links to posts for some reason
     
  6. TigTex

    TigTex MDL Senior Member

    Oct 5, 2009
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    De-solder the bios chip from the motherboard and program it outside the laptop. That way, the write enable line is not pulled low.
    Make sure to backup the corrupted BIOS (or the original bios). There are some bios regions that might be needed to remove "serial number not found" and other errors alike.
     
  7. HP_ENVY_User_32

    HP_ENVY_User_32 MDL Novice

    Nov 2, 2021
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    I ended up doing this shortly after the original posting, and you are correct, this solved the inability to flash the BIOS back into the EEPROM. Unfortunately it seems the modded bios given to me on BIOS-Mods.com damaged other components in the PC as even with the EEPROM soldered back on with the original BIOS... the computer will not boot. I ended up throwing the PCs away.

    The lesson learned here is never take a modified bios from someone whose profile you haven't reviewed to check if they are a reputable Modder.