Can i get general instructions for modifying AMI bios ?

[chaus]

Sad end to the story: seems like i managed to brick the computer

Just has 2 quick beeps every few seconds, and can't get into the BIOS, display is blank.
Tried removing the CMOS battery, and setting the CMOS clear jumpers, but no luck, i think i toasted it.

[Lost_N_BIOS]

Seems like good progress you made, but few things I would note. I doubt changing that exit to zero will help, it might but I doubt it. You need to bypass one of the three infinite loop jumps after (test al, al), likely with EB instead of 74 or 75, but I'd have to look again to be sure. And then yes, you would need to find compatible and working AFUDOS for this model and mod BIOS.

On your replaced edit, did you replace the PE32 same way you removed it before you edited? If you removed the header before editing did you put it back before re-insertion? You have to replace same way you extracted (As-is or body), and be sure if you removed header to put back before re-inserting. If you did all that correctly, then the mod you made was not the correct change and has caused some failure, or the method of flashing in caused a fail (I hate AFU for this, so maybe cause!)

Is this an Intel based system, that has Intel ME? If yes, you should use Intel FPT to dump BIOS region, modify, then reflash the BIOS region.

To fix the current problem you will need to find, if there is, a USB recovery method for your specific model or a general one that might cover Lenovo systems. That, or order a Ch341A or similar flash programmer and SOIC8 test clip cable, these are around $2.50 each on ebay

The BIOS file you're working with is the recovery file name IMAGEFH.rom, so you may just need to put this on the root of a FAT32 USB and then find the correct hotkey/method to invoke recovery.

[chaus]

Ok thanks for letting me know re the infinite loops. If i get it to boot again then i'll find out if i did that correctly.

As for replacing the binary, yes i was careful 'body only' both times.

I'm not sure if it's an intel system or if FPT would work. If i can get it to boot again i'll check that out.

Thanks for the CH341A suggestion. I did some reading about it here, and it seems promising: https://weborus.com/guide-flash-bios-spi...rogrammer/

I've tried putting the original IMAGEFH.rom on a FAT32 USB and booting, i read somewhere that control+home would work, however with no luck. The manual suggests putting a flash update CD in to restore a corrupt BIOS, I presume you simply burn the ISO from their BIOS update site, however that's not an option for the CD-less 'tiny' model I have. Unless i could simply use a USB cd drive but i doubt that'd work.

I think the CH341A is a good idea, really appreciate it. I just need to figure out which chip is the BIOS so i can determine which sized clamp to buy. Would appreciate any suggestions on how to figure that out.

Thanks

[Lost_N_BIOS]

Body only is only needed if you extracted via body only, if you extracted as-is then replaced body only that could cause failure

Yes, CH341A has saved millions of boards, people use them all day long every day. Here's a guide for setting up once you get it
https://www.bios-mods.com/forum/Thread-G...programmer

You would have to find USB recovery method for your model, there wouldn't be a CD method if there is no CD.

BIOS is almost always going to be 8 pin (SOIC8 test clip cable you need), let me know if you need links.
If you want me to help you locate the BIOS on the board, upload some images, it's usually on the bottom side so you only need to remove the back/bottom.

You don't know what CPU is in this system?

[chaus]

Thanks for the link to the CH341A guide, will check it out.
I've found a few SOIC8-sized chips on the motherboard. One of them is right next to the CMOS battery so i think that might be related.
Later i'll write down the numbers on all those chips / upload photos and figure out which one is likely the bios.
Oh the CPU! I thought you meant the motherboard chipset. Yes it's an intel i3 4xxx.
Thanks for your help i really appreciate it.

[chaus]

Ok so here's a photo of the motherboard.
Yellow arrow:
    MXIC MX
    25L6473E
    M2I-10G
    3R174400
    L144215
Red arrow:
    51199
    LAAZ
Green arrow:
    MXIC MX
    25L8006E
    M2I-126
    30423600
    K144075
Blue arrow:
    APL5930
    VQ783
Purple arrow:
    NIKOS
    P12038VA
    GND1Q0K07
Which do you think it is?

[chaus]

My best guess is that it's the 25L6473E (just NE of the coin battery) because that's 64MBit SPI Flash.
The 25L8006E is only 8MBit flash, which seems like it isn't big enough to store the BIOS. Any ideas what'd be on it?
Anyway i guess it's time to buy a SOIC8 cable.

[Lost_N_BIOS]

MXIC MX25L6473E << You are correct, this one would be the Main BIOS
MXIC MX25L8006E << ME or EC etc

These are both BIOS chips, one may be ME or EC, or other partial BIOS data. Only way to know for sure is to dump both and let me check them. No matter what, once your programmer arrives don't write to the chips until I've let you know your backups were done properly. This is for two reasons, one so we get a good copy of any data that is there, and two so you can figure out which software version and chip ID works best for these chips (So you know which to use to write back once ready)

Here's a package with the main CH341A driver and all the software versions, unsure if it's linked in the guide above or not
http://s000.tinyupload.com/index.php?fil...5007472602

[chaus]

So i've purchased a CH341A + SOIC8 clip, should be on its way soon.

I have news however - i tried burning the ISO downloadable version of lenovo's bios onto a DVD, and putting it into a USB-connectable DVD drive and plugging it into the M73. After a minutes worth of beeping (because the screen didn't even work) it rebooted (screen enabled this time) to the normal BIOS. So it appears to be un-bricked now!

Lesson for me seems to be that its likely cheaper (than a ch341+soic8) and simpler to just buy a whitelisted card, or an ethernet->wifi adaptor.

However this is still fun and interesting, so when the programmer arrives i might still give it a shot.

I'm still not sure if there's any way (without the CH341) to upload a modified BIOS without AFUDOS erroring.

[chaus]

I re-read through the thread and saw you recommended trying Intel FPT, so i tried both:

FPT -LIST
and
FPT -verbose -bios -d outfile.bin

And the response (after quite a while) is:

Time out waiting for hardware to complete operation
Error 328: Invalid descriptor