Yes, then no LAN MAC ID here. From your info, the only thing I found in dumped BIOS was the service tag in about 30 places. Lets just see if I can fix your dumped BIOS as is, that will be easier than trying to put all that back in 30 places and get around boot guard at same time (many are in there, so = brick if we try anyway)
No need for other dump, I will find setting change you made in NVRAM and set it back.

I see in stock BIOS, legacy is actually the default, so you must have changed it earlier (or they did before shipping out, but left setup defaults at Legacy)
Boot List, VarStoreInfo (VarOffset/VarName): 0xE15, VarStore: 0x1, QuestionId: 0xBA, Size: 1, Min: 0x0, Max 0x1, Step: 0x0 {05 91 09 13 0A 13 BA 00 01 00 15 0E 00 10 00 01 00}
One Of Option: Legacy, Value (8 bit): 0x0 (default) {09 07 E4 11 10 00 00} << Bold is the default set flag
One Of Option: UEFI, Value (8 bit): 0x1 {09 07 08 13 00 00 01}

So, I just find this in NVRAM, confirm it's now 0x00 and set it back to what you had before 0x01

* Edit - Actually, yes, please setup the other system in the same way you had this one before this happened and then send me a dump
I'm finding ONLY, all areas of the NVRAM and BIOS all have this still set to 0x00, and I expected some would retain the previous 0x01 if this was what is being changed.
That setting is only one that is legacy or UEFI, aside from option rom type loading ones (like where you choose legacy or UEFI video roms to load, SATA rom to load etc)

Maybe it left Secure Boot Enabled, while forcing Legacy? Which would fail, similar to what you mentioned maybe?

You know, you could just program that BIOS onto the non-working system, then I can send you Dell tools to correct the Asset tag, if you wanted to do that instead?

@Lost_N_BIOS, Thanks.

Well that's good about the MAC ID as I spent a few hours digging through registry and logs from the bricked XPS and found nothing, I did find a few other interesting files though, some dumps from BootGuard installations. Also some Dell logs with what looks like a full list of hardware ids etc, not sure if any of it has value to you?

Hmm, interesting... though still a bit over my head at the moment, reading hex is a whole new thing for me.

Okay, I will get that dump as soon as I find a moment, at least it should help to work out the stock to deployed values.

It's just as likely looking at the BIOS Updates, it looks they have been having lots of issues relating to the various boot security elements. I don't really have my head around the process, i'm just putting 2 and 2 together ;)

I'm happy to setup the bios on the operational device to suit the bricked one, then collect a dump. Not sure if I am confident enough to do the Dell Tools/Asset Tag work, i think if it wasn't overly complicated i would be alright, but maybe safer for me to mainly observe at this stage. You don't think i would have the same issues having to change Asset tags in the locked regions? Or do you mean temporarily change the asset tag on the operational device to suit the bricked one?

Thanks again for all the help, it's most appreciated :)

No, I don't need to see any logs or Dell docs etc.

Dell tools to change asset or service tag are easy to use, it's a DOS thing. Sometimes you can even change asset tag / service tag in BIOS, so we'd have to check if that's possible first, you may not even need to use the Dell tools.

What I meant was dump BIOS from working system (once on same version as the bricked one was), and then program it to the bricked system. Then once running again we sort the asset/service tag out through BIOS itself or w/ Dell tools.
Nothing would be changed on the running system, except for you to downgrade BIOS (if it will let you)

@Lost_N_BIOS, Thanks, now I think I understand, that sounds like a good idea to me, if they are only using the Service Tag it should be far easier.

Thankfully the Dell Bios Recovery allows you to roll back to previous versions, I will probably just have to be cautious and disable secure boot etc. *Actually I found a Dell support article just using the .exe in windows.

I have a few busy days ahead, but I will try to get it done today or tomorrow.

I found this documentation on the new Dell Tool, not sure if my device is supported as it's business-focused, https://www.dell.com/support/article/au/...nfigure?lang=en

It looks like they using two asset ids when they change it in the manual.

Thanks again for the help :)
------------------------

@Lost_N_BIOS, just a couple of queries relating to how close the operational XPS settings have to be to the bricked XPS?

Obviously I'm leaving Legacy mode disabled? But should Secure boot be enabled or disabled? Fastboot, I can extend POST for 5 or 10 sec?

Looks like you can only set the Service tag in BIOS if its already unset, same with Asset Id. Probably still have to use DELL tools after flashing.

Thanks, hope your day is going well :)

I'm talking about Dell Engineer Service tools, not something like Command & Configure, I'll send it to you if/when we get there.
Yes, there is usually Asset Tag and Service Tag.

On the BIOS settings, they can be whatever you want once you program it into the bricked system, and they don't need adjusted to anything before you dump from the other system. You can if you want, but it's not necessary
Just enter BIOS, load optimal and save then reboot back to BIOS and change anything you need to whatever you know you need to boot to that ones system.
Yes, as I mentioned, you might not be able to change the tag in BIOS, we'd have to use tools.

Yes, thanks, all is good here, busy busy, but other than that all OK Hope you've been having an OK weekend too!

@Lost_N_BIOS, I hope you are having a very Merry Christmas.

I haven't had much luck with the XPS, the wiring was still setup the same as last time but I just can't seem to get a clean read from the W25Q128FV on the bricked XPS, I get clean dumps from the other smaller Winbond chips on the board using the Raspberry Pi, but not from the W25Q128FV.

Amongst that, I realised that the Black CH341A uses 5V logic for the SPI interface, so i am hoping i haven't damaged the chip. I have purchased a better version of the CH341A but it won't be here for a couple of weeks.

I'm a bit hesitant to try any dumps from the operational XPS until I sort our the programmer. But if you have any suggestions I am all ears?

Thank's again for all the help, sorry for dragging this out, think i owe you some xmas gift cards

@coatman - Thanks, I hope you had a good Christmas as well!!
The 5V stuff about black CH341A can be ignored, that got me concerned early on too, it's fearmongering / unnecessary worries etc.

Did you try with and without main power connected? Are your using the info I posted on post #4
You can dump the operational XPS, nothing will happen as long as you don't erase or write

Hey, @Lost_N_BIOS

Sorry I have been pretty busy and waiting on some parts to arrive, I hope all is well with you.

Thanks for the info on Black Ch341A it had me a little worried.

I have tried with the main power on, but it doesn't recognize the chip.

I now have one of the blue LC technology CH341A modules as well and the same deal I just can't seem to get a verifiable read from the bricked XPS.

I also found a cheap replacement bios chip and that seems to read and verify just fine without being on a PCB.

The only thing I can think of different to last time is that i think I left it sitting with no battery/cmos for a couple of days, I have tried it after 24 hrs but no change, will try again tomorrow.

It almost seems as if something else is writing to the chip during reading as the verification fails at different places on the same read. Also if i look at the bios dumps the variation seems too consistent.

I have attached a few dumps from the LC Tech module and one from the replacement bios chip, https://drive.google.com/open?id=1hx5oVq...8TmhdPKarrhNdWX

I was thinking of trying to write the replacement bios chip dump to the bricked XPS, what program were you recommending?

If you have any suggestions they would be most appreciated.

Thanks again, take care

Hello,

I had the exact same symptoms with my XPS 9550. Bricked it while trying to boot on a USB drive to format it.
Only D+power was showing me some signs of life.
Same things with the fans spinning before shutting down, no access to Bios recovery via CTRL+ESC and the power cord etc...

I just saved it by flashing the Bios with flashrom on windows using this bios :
https://www.badcaps.net/forum/showthread.php?p=915861

(last one)

Made no modifications to it.

I used this CH341a :
https://www.amazon.fr/gp/product/B07RKXS...0?ie=UTF8&psc=1

I think it's what you call the black edition (I didn't know anything about this module a week ago). It was a bit tricky to get the signal from the chip using the clips but after a few tries it works.

Anyway, at first I had the same symptoms but pressing f12 at startup showed me the boot menu and from that i could access the bios and now it's working fine.
I had to reconnect the SSD and change the boot sequence to UEFI and it was good to go.

Hope this helps. A big thank you Lost_N_BIOS for all the information and help you gave on this thread !

@coatman - Sorry for the late reply! For W25Q128FV, please use the method I posted at post #4

@raphaelben - what flashrom build are you using? Can you please link this user over here with it, thanks
Dell XPS 15 9550 Intel ME Cleaner Problem

Also, when you did you dump and or writes, did you have Main battery and or power cable connected or removed, if you remember?