how to unbrick a wintel pro w8?

Okay, I was an idiot, and I borked an OS install on the "hard drive" of a little system-on-a-chip box, a "Wintel Pro," model W8. The borking took out the uefi partition on the "hard drive".

On system boot, it does show the "BIOS" screen, you know, the "American Megatrends, press exit or del to setup." It's not picking up the keyboard at that point, no response to del or exit, and the numlock isn't turning on in response to me pushing the numlock button. The laser on the mouse isn't glowing either, so it's pretty clearly not talking to USB.

Eventually, it goes to an EFI command-line shell. At that point, the keyboard starts working, and the mouse starts glowing. Too bad I have absolutely no idea how to use this shell.

Entering the "exit" command into the shell does bring up the setup "BIOS" screen, with all the options you can tweak. It doesn't seem to be picking up the USB cdrom I have an OS install DVD in as a possible boot device, just the onboard storage device that is currently borked and the USB hub I've got the cdrom, keyboard, and mouse plugged into. (The system only has two USB ports, and plugging just the cdrom and keyboard directly into the system doesn't seem to help.) The USB hub is not exactly a bootable device, and the onboard storage, as I may have mentioned, is currently borked.

Saving changes and exiting the setup screen brings up a "Start PXE over IPv4" message. As I understand it, that means it's trying to boot off of a tftp server on the network. Which might actually be helpful at this point, but all I can find out about it online is that to turn it off you need to tell UEFI to boot off the hard drive. Can't find anything about how to do a Start PXE over IPv4, if you actually need to. Eventually, it stops trying to PXE, and it goes back to the EFI shell.

Any ideas on how to unbrick this thing? It was only a $100, but my dad needs it for dad-type computer things, and I'm between jobs at the moment. If necessary, I could go ahead and replace this thing, but I would really rather not until I start getting paychecks again.

Why were you doing what you were doing when you borked it? What OS was on it? If Linux, take the "drive" out, if you can get it out, put it in any PC with an appropriate interface connection (likely M.2), and try un-borking it. The ESP partition should be recoverable more easily than you might think if all you did was delete its partition table entry or destroy .

If you can't fix it, installing fresh in another PC might work. I've never tried with any Atom, so maybe this is too much to hope for, but not all distros will choke on a change in hardware, especially if the video is the same family. Ideal would be one in the same or close generation to Cherry Trail, maybe Skylake, Kaby Lake or Coffee Lake, all of which are also 14nm process.

Won't it boot a USB stick plugged in directly with everything else USB on the hub? USB access problems can sometimes be solved with a BIOS reset, or update, to clear corruption or an accidental and unusable USB setting change. Sometimes getting into the BIOS requires DEL or other requisite key (F2, F10, others) be struck before anything appears on screen, sometimes in a very time sensitive manner.

Lots of Google hits for "PXE host setup".

What OS was on it? If Linux, take the "drive" out

W8 = Windows 8, system-on-a-chip = eMMC drive, Embedded onto mobo, can't pull it out.

Originally Posted by crazyeddie740 Entering the "exit" command into the shell does bring up the setup "BIOS" screen, with all the options you can tweak. It doesn't seem to be picking up the USB cdrom I have an OS install DVD in as a possible boot device, just the onboard storage device that is currently borked and the USB hub I've got the cdrom, keyboard, and mouse plugged into.

If this is Windows 8.1 with Bing, you will need that particular IS0 in order for a new install over the existing to activate it with embedded product key. The Windows 8.1 from MS site will not activate on a machine that came with Bing. Someone however did put one together and I did download it from a torrent last year, it was 32bit which is what I needed anyway to recover a friends Acer tablet with detachable keyboard. It basically has same setup as yours except it had a display.

You should be able to repair the current installation using WindowsPE 8.1, the one in the link is command line only but that is all that is required since you need to use command line to restore the boot files in the EFI partition. You would need to run diskpart to format and assign a drive letter to the EFI partition if the partition still exist, which I would bet it does still exist. Then once you've assigned the EFI partition a drive letter, using diskpart command: list vol will show the drive letters assigned to both EFI partition and Windows partition, then you exit diskpart utility and run the command below to rebuild the proper Windows boot files in the EFI partition:

bcdboot C:\Windows /s S:\

The command above assumes the Windows partition's letter is "C", and the letter you assigned to the EFI partition is "S". The "/s" is required to tell bcdboot to create UEFI boot.

A few things you can try that helped me with similar setup:
The CD drive likely spins up too slow for the UEFI firmware to find a bootable medium, I suggest burning the ISO to USB key with Rufus. There are utilities that can install your Windows ISO to USB creating a Windows live giving you a running operating system instead of an installation disk, the one I use is WinToUSB_Free, this would be the same as a WinPE such as the link provided above except you would have a full operating system with desktop and all, but you'll still be resorting to the command line running as administrator. WinToUSB_Free may refuse to install the Enterprise version, Microsoft limitation I'm guessing.

Another trick I had with the Acer: In BIOS it allowed to manually add a boot device to the menu, and delete boot devices from the menu. If you have the option to do this and the USB key still does not appear in the list of bootable devices, deleting the default on-board eMMC drive from the menu may avoid errors and force the firmware to search harder and find the USB and since that's the only bootable device, it may then boot it. That's something I remember doing with the Acer, and I also had to use a hub to get mouse, and extra USB data key for transferring files, I was able to boot Gandalf's WindowsPE (custom PE with desktop) from either the hub through OTG adaptor on the tablet or the USB port on the detachable keyboard.

EDIT: Also, the Windows PE may also have similar options to WinRE (Windows recovery environment) with GUI click here to attempt a boot repair etc.

Oh!
One more thing
The technology used with Windows 8/8.1 on a 32GB eMMC. Most often if not always, it uses Wimboot technology. There will be a Windows recover partition and many OEM will allow you to boot to this partition from the UEFI settings (BIOS) to a Windows recovery environment which will give you the options to either attempt a boot repair, recover from a drive image or recover from this partition which contains a compressed image of the OEM installation.

Wimboot: The files in C drive are just pointer files to the actual files in the image in the recovery partition, this way the space used up in C drive is very small compared to a full install in the C drive, which in turn gives the user adequate space for personal data and critical updates. If you do a native install in C drive, you won't have much leftover space, and if you fill the drive to the max (applying updates is enough), the chip will get locked and it's borked again. It can be unlocked but you need to clear out some stuff to get some free space back. Many folks ended up trashing there units taking the free upgrade to Windows 10 which does not use Wimboot, that's strictly a Windows 8 thing.

So...It is best to try and recover the original configuration ---> Wimboot.

The Acer I recovered required installing the Windows 8.1 wBing to an external drive, activate it, then create a Wimboot image of it and rebuilding the entire eMMC to original configuration with the image in the recovery partition and applying the pointer files in C drive. It was like new without most of the Acer related bloatware, some of the Acer stuff I did install for specific hardware functionality.

Yeah, it's a system-on-a-chip, so no way to remove the "drive."

As for how the borking occurred, well, I was trying to install Ubuntu and get rid of the Windows. I noticed that it was picking up the miscro-sd (unlike the Debian install), so I stupidly did a hard shutdown so I could go back to the formatting stage of the install and use a micro-sd card as a /home partition. (The damn thing only has 32 GB of onboard storage.) That would have worked with an old-school BIOS, but I neglected to take UEFI into consideration before my muscle memory hit the power switch. ... I think new UEFI partition was only partially installed before I did the hard shutdown. ... so there may be some important bits of that partition missing... I seriously doubt the Windows recovery partition is still there.

I don't particularly want to reinstall Windows, unless that's a necessary step to getting the UEFI working good enough to install some flavor of Linux.

Okay, for setting up a PXE host, found this https://www.tecmint.com/install-pxe-...r-in-centos-7/ It's relatively easy to follow, but I don't think the author was a native speaker of English, and I'm not sure how well the directions will go with the various flavors of linux I have lying around. At least I have some Raspberry Pi 3s laying around that I can plug into the router to use as the PXE server. Then I just have to figure out how to tell the PXE client on the wintel box to boot off the server. (Assuming that its little memory banks aren't too damaged for that.)

I didn't think about trying thumb drive instead of an optical. Yeah, the spin-up might be a problem, but I wish I knew what was causing the USB keyboard and mouse not to work during the initial boot. I'm afraid it's just plain not talking to USB until much later in the boot process (like when it goes to the EFI shell). I'm guessing that some UEFI-level drivers have gone off the big /dev/null in the sky. I'll give the thumb drive a shot, and then try to figure out the mysteries of PXE if that doesn't work.