(UEFI) Dell XPS 15z L511z modded BIOS - and HOWTO

[TimeWalker]

Well, it seems that I'm not playing a Columbus here as the method apparently has been described by Ryan HERE
But .. again arises the mighty 'but'... he bricked his machine and possible corrupted the boot block those he was unable to reflash. According to a post from MDL the BIOS.cap has to be extracted using 7z from the OEM updater. But ... (again) the F33 part of the firmware he is referring to is identical in size to FvRecovery.fd file found in winflash's temp folder ? Shouldn't it have been used ? (I only assume that because it's called Recovery for a reason lol ... )

Anyway, I'm rambling here .. I got my hands on a Insyde bios rom from a Toshiba laptop that initiates the boot block with Fn+F ... the CdExpress module also has BIOS.cap string in the module, but the name of the recovery file the person reported working was based of off the platform model ..

[jkbuha]

no fawar - the instructions are not as per those guidelines. they are as per the first post in this thread. I'm going to make it extra special easy

go to the winflash folder that was created when you last flashed your bios. if you dont have one, download an original 15z bios and double click on it to start. don't flash the bios, instead copy the winflash folder that was created in your temp folder to another directory, eg: c:\winflash. copy the new hacked bios to this folder, go to c:\winflash and run the following instruction: winflash.exe /BIOS /EC /SA /SV /BBL "BIOS1_A11.....WPH"

[jkbuha]

Hi TimeWalker - quick question. When you recovered your BIOS by accident, was the usb filename BIOS.cap? Also have you tried pressing Fn+ESC straight from powering up the machine?

[TimeWalker]

Yes I did have the BIOS.cap file along with FvRecovery.fd on the usb flashdrive. The FN+Esc + power button will not initiate anything, because dell has set Fn to initiate ePSA diagnostics utility. Going back through the post in the thread I have found a post from Ryan describing how he was trying to revive his bricked machine by having BIOS.cap that he has renamed from partially extracted rom's F33 part of the firmware. This pars appears to be identical in size with FvRecovery.fd .. on Inyde bioses this is the file that they rename and then use for recovery. Ryan however apparently butchered his boot block so he wasn't able to initiate the recovery process again nor he was able to boot into the OS since it was a bad flash. At least he figured that the End key trigger the CdExpress to read the file of off the external media.

[jkbuha]

Thanks TimeWalker. Am having problems reading my posts in this thread - not sure if this is due to my browser or the forum database, so apologies if you see any multiple entries

[TimeWalker]

I can bet you a nickel (yes lol I'm THAT cheap) that the End key is the trick.
Try unplugging the power lead, hold down the End key, pug the power brick back in and press the power button.
If you don't have a flashdrive in won't power on, nor it would power automatically when you plug in the power lead... which only means it hasn't fount a proper recovery file on the external media. Interestingly enough if you were to press and hold any other button other than End and proceeded to turn on the machine via the power button it will turn on with pretty much any key held down. Anyone wanna try it on theirs XPS?

So the problem (a) is solved - the hotkey combination to initiate recovery is known. The problem (b) - filename is also solved .. the method to extract BIOS.cap (using 7zip) is known, it might be the FvRecovery.fd file that I had on the stick that might have initiated the process, but it is known how to get it as well .. I guess it's time to combine the knowledge ?

[jkbuha]

yes confirmed on my xps 15z (no removable battery). pressing power+end starts scanning the usb drive. I'm just not sure on the filename + contents now. I'm assuming that fvrecovery.fd file initiates the recovery (ie: the recovery flash program), but we most probably need another file (bios.cap?) to flash full bios.

[kasar]

I can try this while I will be at home tonight.

anyway correct me if I am wrong about the procedure

1 - rename FvRecovery.fd file to BIOS.cap and place it on the root of a usb drive.
2 - turn off the system
3 - unplug the battery
4 - make sure the usb drive with bios file is plugged in.
5 - hold down the end key
6 - power on the system while holding end key.

is this correct?

[TimeWalker]

FvRecovery.fd contains the DXE core, PEI core and lots of drivers, which are mainly User Interface-related among which is the FwBlock (boot block). But there indeed is no CrisisRecovery module to be initiated.

kasar,
- (1) get your FvRecovery.fd from WinFlash temp folder and rename it to BIOS.cap
- (2) optionally get your BIOS.cap by opening the official flasher with 7z and go .rsrc > 1024 > RCDATA > rename the 7000 file to BIOS.cap
- format your < 4Gb flashdrive as FAT32 or FAT (FAT16=FAT is what dell uses for their OEM partition)
- put (1) into the root of your flashdrive
- power down your laptop, remove the power lead .. leave the battery in.
- plug the USB flashdrive into a usb port that is not a eSata/comboport
- hold down End key and plug in the power lead. keep holding for a couple of seconds then let go of End key.. the machine should boot up at this point and your flashdrive should start blinking (I have no usb drives with a LED .. so i'm kind of screwed on this one lol) but backlight won't come on. In case it didn't boot up then remove the power lead, press End again, plug the power lead in and press power button and let go of End key.
Vid is here on how to initiate it, in case you fail miserably: https://www.dropbox.com/s/yosxmao7y6zdg5...170603.m4v
- if nothing happens try with (2) on the usb flasdhrive instead


P.S. make sure you don't accidentally interrupt the flashing process (that's why leave the battery in place) as the boot block will get damaged on the actual chip those you won't be able to initiate recovery in the future ..

[kasar]

ah ok, wich file I should pick then as BIOS.cap?

bios1.wph file?

one of the big files inside the bios1.wph file?