Hi all,

Been lurking for a little while now and have been struggling to figure any of this out as I'm still learning (complete beginner to be honest)

I've attached a bios from a Tesco Hudl 2, baytrail tablet, that I've been trying to get windows 10 to boot on.

A fellow modder from another forum (Modaco) has managed to disable the secureboot option to be able to boot from USB but there's no way to actually enter a UEFI menu or anything to see what menus/options there are. I know something exists because I've accessed a boot manager menu by mistake a few times now so I'm certain there must be more.

When trying to load windows 10 I get ACPI BIOS ERROR when trying to boot off USB which apparently means the ACPI isn't compatible or something along those lines but without access to the bios menu there's no way to change it/turn it off to enable boot.

I'm hoping someone here might be able to take a look at the attached and see if they can make heads/tails of it?

Thanks in advance!

@dazmatic - no BIOS attached or linked, so I can't look to try and help. So, you can't enter a "BIOS" at all?

I did attach it previously, just obviously never uploaded. So that bios is one that's already has the bit flipped for the secure boot to enable booting from USB

Thanks, I will check it out now. So, you can't enter any kind of BIOS at bootup?

* Edit - yes, I can modify this BIOS, lots of settings you can change too, but I'm unsure which ones you need set to what. I see this, maybe this is only one you need changed (well two here)


Also, this may need changed, but to which option I'm not sure, you'd have to read about each type and see if you can decide


And, some of these may need changed too, especially last one if you want to install windows

That's amazing. I'm at work at the minute so I can't check which I need but I'd certainly like to know how you're inspecting the bios like that?

I can't get into any bios options. It looks like it simply fast boots, bypasses any loading screens and goes straight into android so being able to get into a bios menu would be a great start, being ble to change acpi settings would be even better as I might be able to load windows.

Thanks so much for looking into it.

You're welcome!

Here is text format of some settings also that can be changed without using that tool - default settings in this are shown via "(Default)" like you see below, these can be changed via hex edit, moving the bolded "10" in this example to the same location on the desired setting, and putting "00" in place of original default "10"
http://s000.tinyupload.com/index.php?fil...167764249341142

Boot Performance Mode, VarStoreInfo (VarOffset/VarName): 0x102, VarStore: 0x1234, QuestionId: 0x9, Size: 1, Min: 0x0, Max 0x2, Step: 0x0 {05 91 E5 01 E6 01 09 00 34 12 02 01 10 10 00 02 00}
One Of Option: Max Performance, Value (8 bit): 0x0 (default) {09 07 E7 01 10 00 00} << That "10" is what tells BIOS this is the default, it can be moved to either of the other two instead (this applies to all settings in above file, except some may use "30" instead of "10" possibly, I didn't check all)
One Of Option: Max Battery, Value (8 bit): 0x1 {09 07 E8 01 00 00 01}
One Of Option: Auto, Value (8 bit): 0x2 {09 07 08 00 00 00 02}

The tool I used to show you the images above is Intel Insyde tool H20EZE - this may or may not break the BIOS upon edit/save, I have not checked/tested yet, but this would not be what I'd use to edit the BIOS anyway, only used it as an easier and quicker way to show you some settings in a visible manner
You can get it here from Releases tab at link below, download V1.1 package and inside you will find all versions and many Intel Insyde tools (Version used for those images - 100.00.02.13)
https://github.com/mikebdp2/Insider_BIOS_Tools

Since you cannot enter BIOS at all, that could mean it's somehow disabled, which I didn't check for yet, or Fast Boot may be enabled too which always causes issues like that. (And yes, I checked just now, this is enabled - shown in "Maybe2 image above)
Removing the battery and booting might disable this, and then let you enter BIOS. You can also try holding down the key that you think lets you go into BIOS, before powering on, then keep holding as you power-up.
Removing the boot/hard drive might also allow BIOS entry. Clearing and resetting CMOS Might disable fast boot too, less likely here since it may be the default value. Win10 has a special restart menu to get you in there, but it would need to be installed first too so not helpful

What may be easier here, does this model have a "brother/sister" model that by default used Win10 instead of Android? If yes, and you have a programmer, you can program in that BIOS instead. Sometimes this may be required, since Win/Android ROM may only be present in each respective BIOS.
If this doesn't have a similar model for windows, then both ROMs may be present in this BIOS

That's ace, thanks for the suggestions! I'll have a look later.

Because it's a baytrail tablet and subsequently discontinued by Tesco, there's no support online at all so this is a massive help and I really hope it helps others because they're great tablets with decent hardware but the software and updates were so buggy that they fell over constantly or drives got corrupt or bios updates failed.

I'm a good solderer and have a ch341 tool and so reading and flashing a bios is no issue.

I do have another question however if you don't mind, I have a firmware volume for one of these tablets, before they made the switch to a 64bit efi. Me being a fool had 1 tablet which worked and wanted an image of the disk to restore to another and flashed the secure boot disabled bios to do so this without making a backup, not aware it was previously 32bit only. I got the image but the bios I suspect is now expecting a 64bit efi and won't boot as there's only bootia32.efi in the ESP partition. The firmware volume is the last update made before the switch to 64bit and I'd love to get a 32bit bios on it again to see it'll still boot the 32 bit android OS.
Once again, I'm not sure if it's possible or even if I'm just talking gobbledegook but I'd appreciate your insight!

You're welcome! Good to know you can solder and reprogram BIOS, that makes me feel better about possibly sending out test edits for you

About this 32/64 BIOS thing, I've never heard of such a thing BIOS-wise but I don't often mess with anything specifically setup for Android, but the way you describe it and this "ESP" Partition, is that something on the hard drive?
If yes, can't you just clone or setup a x64 hard drive similar to your other one, or copy in a bootia64.efi then BIOS would get what it expects and boot it the OS?

Lets try to disable Fast boot without a BIOS Mod, can you boot to a USB stick (Default for this is enabled so you should be able to)? If yes, we can boot to UEFI grub and use setup_var to try and change the current setting, then see if you can get in BIOS or not.
If not, remove main HDD/SSD and try again, see if you can boot to USB or enter BIOS too while HDD is removed.

Here is my guide on this, for another purpose, but you can use too, start around step #5-6, below is the variable you want to change to disable Fast Boot
[GUIDE] Grub Fix Intel FPT Error 368 - BIOS Lock Asus/Other Mod BIOS Flash
Alt boot to grub when no boot to EFI on exit page (You'll probably need to do this method) - [Help needed] Hidden Advanced menu Bios HP Z1 J52_0274.BIN (2)

First >> 0x65 (Current default = 0x0/enabled)
Possible second, but unsure >> 0x169

So at grub prompt you'll type the following (1=disabled) >> setup_var 0x65 0x1
Then reboot, and see if you can enter BIOS with or without main HDD attached.

So the ESP partition on android is the equivalent of the Boot folder on a linux install, except it has a partition all to its own. It's where the EFI is stored. I realised I'd made the mistake when I looked at the partition and saw the bootia32.efi, when compared to the next available over the air update, there's only a bootx64.efi available with another bios update firmware volume so presumably, there was a change made to the bios to allow booting 64bit efi but also prevented booting 32bit. Doesn't make much sense I know but it's the only explanation that does.

I'll have a try with your method, unfortunately, there's no HDD to remove, only an EMMC chip which, whilst I've got hot air reflow and solder stencils, don't fancy playing with BGA's just yet.

I'm also making a pogo pin adapter for the programming pads on the PCB, much better than having to solder to them each time, quite handy having a laser cutter/3D printer selection at my disposal!

Thanks so much for your help and info though. There's literally next to no information online so I seriously hope these efforts help someone else!


So, your bootable msdos USB didn't work. Fortunately, I already had a linux live repair USB handy which I knew did, so, I renamed the existing EFI files to .old and added in the ones you provided and was able to boot into the grub shell.

Likewise, the setup variable program worked and was able to access current variables and change them, even then read the variables back to confirm.

that being said. When reading them back, I get the variable has been changed to 0x01 and not 0x1. Should it be 0x10?

Eitherway, changing it to 0x1 did not work I'm afraid, but hey, I'm pleased I'm able to change anything at all, without the need for bios modding hex files


Yeah, still not been able to access the setup menu. I'll have a play with acpi settings to see if I can get windows 10 to boot. Would be great to know what variable the acpi PCI setting is from your first picture?

Is it possible to modify a bios to boot from a bootia32.efi? I know the file is on the drive and the only thing that's changed is the bios version, it states that theres no bootable device found.

It's annoying because I just got hold of another tablet with (I presume) a 32bit bios which I've backed up, flashed it to this other previously working tablet and still refuses to boot!

@dazmatic - I'm not familiar with Linux either, glad you are so you can try to convert my thoughts to apply towards all this So, on the EMMC, can you some other way (SPI cables, other pins, contact points, cables etc) access the drive raw outside of the boards use?
Thinking maybe you could do what I mentioned, somehow, connecting that way instead of even considering removing and replacing

Yes, sorry about the USB, I didn't consider, you probably needed to create a GPT partition instead and set it up that way, instead of MBR method. So probably exactly how you already had it

Read the variable first via >> setup_var 0xVariableID (No setting following that) and it should readout the default like it does after you try to set a setting. but in general, yes, often I will enter 0x01 or 0x1 and it will tell me opposite than I input, but yes it changes the setting anyway.

If you can get win10 booting, I can show you how to exit to BIOS, there is special method of exiting or troubleshooting that will lead you to this when Fast Boot enabled. I'll have to find it again, but once you get Win10 going I'll hunt it down

I'd have to have a 32/64 "BIOS" copy to compare to see about your bootia32.efi thing, in the current BIOS you sent me I cannot find anything relating to 32/64 bit (yes, checked x86, 32-bit, 32 bit etc), nor can I find bootia mentioned, so I don't know where this is being set.
But yes, probably once I can find, then I can change for you, it's probably in code I'd have to edit in assembly hex, but I don't know what module so I can't dig around.

Why do you presume this other one now is 32bit too? Does it have the bootia32.efi on it? If yes, send me that BIOS, maybe by comparing that one and the other I can find where this is set.

Zitat von Lost_N_BIOS im Beitrag #10

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@dazmatic - I\'m not familiar with Linux either, glad you are so you can try to convert my thoughts to apply towards all this So, on the EMMC, can you some other way (SPI cables, other pins, contact points, cables etc) access the drive raw outside of the boards use? Thinking maybe you could do what I mentioned, somehow, connecting that way instead of even considering removing and replacing

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Zitat von Lost_N_BIOS im Beitrag #10

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Yes, sorry about the USB, I didn\'t consider, you probably needed to create a GPT partition instead and set it up that way, instead of MBR method. So probably exactly how you already had it

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Zitat von Lost_N_BIOS im Beitrag #10

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If you can get win10 booting, I can show you how to exit to BIOS, there is special method of exiting or troubleshooting that will lead you to this when Fast Boot enabled. I\'ll have to find it again, but once you get Win10 going I\'ll hunt it down

I\'d have to have a 32/64 "BIOS" copy to compare to see about your bootia32.efi thing, in the current BIOS you sent me I cannot find anything relating to 32/64 bit (yes, checked x86, 32-bit, 32 bit etc), nor can I find bootia mentioned, so I don\'t know where this is being set.
But yes, probably once I can find, then I can change for you, it\'s probably in code I\'d have to edit in assembly hex, but I don\'t know what module so I can\'t dig around.

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Well hopefully you can get Win10 going by changing that ISP PCI option, once your battery is charged up. You may/should probably also change that one setting "OS Selection" to Windows too instead of Android
No BIOS was attached to your post

I've reattached, should be there now.

Changing those settings meant Windows 10 now installs which is awesome, but the battery died whilst copying files.

@dazmatic - Yes, file attached now, thanks. Sweet you are getting windows installed! Wow, sounds like a bad battery if it's dying so fast, or did you just not let it charge up enough yet? Can't you can't connect it to AC?
Did you ever get into a BIOS interface yet?

I compared the BIOS some, and besides some BIOS settings differences between the two that don't matter, only due to newer/better BIOS (Like more sensor, different battery and different charger options, etc) most is all the same and set the same too.
But, I do see on the 32bit BIOS, you can set Legacy or Dual (Legacy/UEFI) boot option type. So on that system, you can install MBR system if you want, and with that set too it should disable Fast Boot by default allowing you to be able to enter the BIOS
And I checked the browser strings and setupbrowser files, it's designed to let you in the BIOS because all the controls, text and help are there and setup correctly.

I just noticed this too (about Fast Boot Option) it's helps says "If enabled the system firmware does not initialize keyboard and check for firmware menu key." so it's not even turning on the KB for you to be able to try to enter BIOS when this is enabled, only will go there is this is disabled and then you hit the hotkey (or remove HDD)
This is enabled on both systems, to disable use setup_var 0x65 0x1 on both BIOS (default or to re-enable do same, but 0x0)

Maybe this setting would help with the 32/64 booting? This would have to be changed via BIOS mod, change the setting in EZH20 and reflash
I can't find variables for any of those in the setup IFR, everything above "Advanced CPU control" is missing, so BIOS edit only on this one. I did a test edit and save, and BIOS looks OK after, so I think it's OK to edit w/ H20EZE V.100.00.02.13


Also, another way you can get into BIOS I see, this setting "Automatic Failover" default is Enabled "if boot to default device fail, it will directly try to boot next device. Disable: if boot to default device fail, it will pop warning message then go into firmware UI."
Change this setting to disabled, and remove HDD somehow? To change this via grub >> setup_var 0xDE 0x0 (Default is 0x1) But, I do think disabling Fast Boot will allow you to use keyboard key to enter BIOS (Unsure of key, F1 or F2, ESC, or Del, or maybe F12)

So a friend over on the Modaco forums has unlocked the secure boot feature on the 32bit bios so I'm flashing that now with a known working 32bit android image on the SSD. I know the bios won't boot android but I'm hoping that a few changes if settings like those you've mentioned might get somewhere.

EDIT:

So trying either the 32bit normal or 32bit secure boot off bios doesn't boot at all. However, you mention the USB. In previous efforts, I disabled the USB hot key support and got exactly the same scenario that I've got now, where it doesn't boot and looking at the bios, it's disabled so I've no way to enable it without modding the bios directly but not really sure what the variable is let alone how to do it in hex.