ich9utils


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Introduction

The ich9utils utility in Libreboot is used to manipulate Intel Flash Descriptors for ICH9M on laptops such as ThinkPad X200 or T400. Specifically, the ich9gen utility can generate 12KiB descriptor+GbE files for inserting into the start of a ROM, where everything after that is the BIOS region. These are special descriptors with the Intel ME region disabled, and Intel ME itself fully disabled.

ich9utils is handled by the lbmk (libreboot-make) build system, but the code itself is hosted in a separate repository. You can check the Git repositories linked on ../../git.html if you wish to download and use it.

It is very uncommon, on GM45/ICH9M systems, to have an Intel Flash Descriptor and GbE but without an Intel ME. On most of these systems (without Libreboot, Libreboot or coreboot), there is either descriptor+GbE+ME+BIOS or just BIOS, where on systems with just the BIOS region an Intel GbE NIC is not present. In Libreboot (and Libreboot), we provide descriptor+GbE images with Intel ME disabled and not present in the ROM; this enables the Intel GbE NIC to be used, while not having an Intel ME present. A consequence of this is that the malicious features of ME (such as AMT) are not present, however the Intel ME also handles TPM which is therefore disabled in this setup.

NOTE: If you accidentally flash a ROM without descriptor+GbE, it will still work but the Intel GbE NIC will be dysfunctional. If you do that, just boot up and correct the problem (and you can use a USB/cardbus/expresscard NIC or WiFi for internet if necessary). That is the main reason why ich9utils was written in the first place; it was already very possible to boot without an Intel ME by simply not having a descriptor or anything in ROM, just coreboot. The purpose of ich9gen specifically is to get the Intel GbE NIC working but without the Intel ME being enabled!

ICH9 based systems were the last generation that could be booted without an Intel ME. Future platforms (such as Sandybridge and Ivybridge) require an Intel ME since the ME on those platforms also handles power management and some minor initialization functions. On ICH9 based systems (such as X200 or T400) the Intel ME only handles AMT and TPM, and there’s no 30 minute timer (if you boot later platforms without an Intel ME and descriptor, or invalid Intel ME firmware, the system will either not boot or will turn off after 30 minutes per a watchdog reset timer).

More information about the ME can be found at http://www.coreboot.org/Intel_Management_Engine and http://me.bios.io/Main_Page.

Another project: http://io.netgarage.org/me/

ich9utils

You can find ich9utils on the Git page or you can download lbmk from the same page and run the following command in there:

./build module ich9utils

You can also find it in the source code tar archives, on Libreboot releases.

In lbmk, you can use the following command to generate descriptors:

./build descriptors ich9m

The Libreboot build system will use the descriptors under descriptors/ich9m when building ROM images for these machines.

Alternatively, you can just clone ich9utils directly and run make in the directory, and run the ich9gen program directly.

ICH9 show utility

The ich9show utility outputs the entire contents of the descriptor and GbE regions in a given ROM image as supplied by the user. Output is in Markdown format (Pandoc variant) so that it can be converted easily into various formats. It could even be piped directly into pandoc!

ICH9 gen utility

When you simply run ich9gen without any arguments, it generates descriptor+GbE images with a default MAC address in the GbE region. If you wish to use a custom macaddress, you can supply an argument like so:

ich9gen --macaddress 00:1f:16:80:80:80

The above MAC address is just an example. It is recommended that you use the MAC address officially assigned to your NIC.

Three new files will be created:

These files contain the descriptor+GbE region and are suitable for systems that have an Intel GbE NIC present. The flash regions (as defined by the Intel Flash Descriptor) are set read-write which means that you can also re-flash using flashrom -p internal in your operating system running on that machine. This is the default setup used when Libreboot’s build system compiles ROM images.

Alternative versions of these files are also created, which have ro in the filename. If you use those versions, all flash regions (as defined by the Intel Flash Descriptor) will be set to read only. This can be useful, for security purposes, if you wish to ensure that malicious software in your operating system cannot simply re-flash new firmware.

The region setup created by these descriptors is as follows:

The GbE region contains configuration data for your Intel GbE NIC. You can find information about this in Intel datasheets, and it is very well described in the ich9utils source code.

Assuming that your Libreboot image is named libreboot.rom, copy the file to where libreboot.rom is located and then insert the descriptor+gbe file into the ROM image.

For 16MiB flash chips:

dd if=ich9fdgbe_16m.bin of=libreboot.rom bs=12k count=1 conv=notrunc

For 8MiB flash chips:

dd if=ich9fdgbe_8m.bin of=libreboot.rom bs=12k count=1 conv=notrunc

For 4MiB flash chips:

dd if=ich9fdgbe_4m.bin of=libreboot.rom bs=12k count=1 conv=notrunc

If you wish to have read-only flash (write protected flash), substitute the above examples with descriptor+GbE images that have ro in the filename. RO here means read only, not Romania!

The above commands assume that in coreboot you have specified the CBFS size as no more than the size of the flash, minus 12KiB.

NOTE: ich9gen also generates descriptors without a GbE region, where in those descriptors the Intel GbE is not specified. Those are highly experimental, and theoretical since no such system exists in the wild where ICH9 is used, no Intel GbE NIC present and descriptor present; on such systems, the vendor will just supply a descriptor-less setup. Those GbE-less descriptor images created by ich9gen are only 4KiB in size, and should never be used except for fun, like, basically shits and/or giggles.

For shits and giggles, R500 ROM images in Libreboot use these no-GbE descriptor images generated by ich9gen. However, a descriptorless setup would also work just fine. ThinkPad R500 doesn’t have an Intel PHY in it, and it instead uses a Broadcom NIC for ethernet. In descriptorless mode, ICH9M works very similarly to older ICH7 chipsets.

Your libreboot.rom image is now ready to be flashed on the system. Refer back to ../install/#flashrom for how to flash it.

Write-protecting the flash chip

The ich9gen utility (see below) generates two types of descriptor+GbE setup:

Read on for more information. Use the ro files mentioned below, and your flash will be read-only in software (you can still externally re-flash and read the contents of flash).

For ease of use, Libreboot provides ROMs that are read-write by default. In practise, you can boot a Linux kernel with access to lower memory disabled which will make software re-flashing impossible (unless you reboot with such memory protections disabled, e.g. iomem=relaxed kernel parameter).

ICH9 deblob utility

This was the tool originally used to disable the ME on X200 (later adapted for other systems that use the GM45 chipset). ich9gen now supersedes it; ich9gen is better because it does not rely on dumping the factory.rom image (whereas, ich9deblob does).

Simply speaking, ich9deblob takes an original dump of the boot flash, where that boot flash contains a descriptor that defines the existence of Intel ME, and modifies it. The Intel Flash Descriptor is modified to disable the ME region. It disables the ME itself aswell. The GbE region is moved to the location just after the descriptor. The BIOS region is specified as being after the descriptor+GbE regions, filling the rest of the boot flash.

The GbE region is largely unedited when using this utility.

Run it like so, with factory.rom in the same directory:

./ich9deblob

The factory.rom file is your dump of the vendor boot flash. Older versions of this utility have this file name hardcoded, and for compatibility reasons it will still work in this manner. However, you can now specify your own file name.

For example:

./ich9deblob lenovo.rom

A 12kiB file named deblobbed_descriptor.bin will now appear. Keep this and the factory.rom stored in a safe location! The first 4KiB contains the descriptor data region for your system, and the next 8KiB contains the gbe region (config data for your gigabit NIC). These 2 regions could actually be separate files, but they are joined into 1 file in this case.

A 4KiB file named deblobbed_4kdescriptor.bin will alternatively appear, if no GbE region was detected inside the ROM image. This is usually the case, when a discrete NIC is used (eg Broadcom) instead of Intel. Only the Intel NICs need a GbE region in the flash chip.

Assuming that your Libreboot image is named libreboot.rom, copy the deblobbed_descriptor.bin file to where libreboot.rom is located and then run:

dd if=deblobbed_descriptor.bin of=libreboot.rom bs=12k count=1 conv=notrunc

Alternatively, if you got a the deblobbed_4kdescriptor.bin file (no GbE defined), do this:

dd if=deblobbed_4kdescriptor.bin of=libreboot.rom bs=4k count=1 conv=notrunc

(it’s very unlikely that you would ever see this. Descriptor without GbE is very rare, probably non-existant, but theoretically possible and this functionality is implemented based on Intel datasheets)

The utility will also generate 4 additional files:

These are self-written by ich9deblob. The ich9gen utility was created, based on this very functionality, with some tweaks made afterwards.

These are C source files that can re-generate the very same Gbe and Descriptor structs (from ich9deblob/ich9gen). To use these, place them in src/ich9gen/ in ich9deblob, then re-build. The newly build ich9gen executable will be able to re-create the very same 12KiB file from scratch, based on the C structs, this time without the need for afactory.rom dump!

You should now have a libreboot.rom image containing the correct 4K descriptor and 8K gbe regions, which will then be safe to flash. Refer back to index.html/#gm45 for how to flash it.

demefactory utility

This utility has never been tested, officially, but it should work.

This takes a factory.rom dump and disables the ME/TPM, but leaves the region intact. It also sets all regions read-write. Simply put, this means that you can use the original factory firmware but without the Intel ME enabled.

The ME interferes with flash read/write in flashrom, and the default descriptor locks some regions. The idea is that doing this will remove all of those restrictions.

Simply run (with factory.rom in the same directory):

./demefactory

It will generate a 4KiB descriptor file (only the descriptor, no GbE). Insert that into a factory.rom image (NOTE: do this on a copy of it. Keep the original factory.rom stored safely somewhere):

dd if=demefactory_4kdescriptor.bin of=factory_nome.rom bs=4k count=1 conv=notrunc

Use-case: a factory.rom image modified in this way would theoretically have no flash protections whatsoever, making it easy to quickly switch between factory/Libreboot in software, without ever having to disassemble and re-flash externally unless you brick the device.

The sections below are adapted from (mostly) IRC logs related to early development getting the ME removed on GM45. They are useful for background information. This could not have been done without sgsit’s help.

Early notes

Flash chips

Early development notes

Start (hex) End (hex)   Length (hex)    Area Name
----------- ---------   ------------    ---------
00000000    003FFFFF    00400000    Flash Image

00000000    00000FFF    00001000    Descriptor Region
00000004    0000000F    0000000C        Descriptor Map
00000010    0000001B    0000000C        Component Section
00000040    0000004F    00000010        Region Section
00000060    0000006B    0000000C        Master Access Section
00000060    00000063    00000004            CPU/BIOS
00000064    00000067    00000004            Manageability Engine (ME)
00000068    0000006B    00000004            GbE LAN
00000100    00000103    00000004        ICH Strap 0
00000104    00000107    00000004        ICH Strap 1
00000200    00000203    00000004        MCH Strap 0
00000EFC    00000EFF    00000004        Descriptor Map 2
00000ED0    00000EF7    00000028        ME VSCC Table
00000ED0    00000ED7    00000008            Flash device 1
00000ED8    00000EDF    00000008            Flash device 2
00000EE0    00000EE7    00000008            Flash device 3
00000EE8    00000EEF    00000008            Flash device 4
00000EF0    00000EF7    00000008            Flash device 5
00000F00    00000FFF    00000100        OEM Section
00001000    001F5FFF    001F5000    ME Region
001F6000    001F7FFF    00002000    GbE Region
001F8000    001FFFFF    00008000    PDR Region
00200000    003FFFFF    00200000    BIOS Region

Start (hex) End (hex)   Length (hex)    Area Name
----------- ---------   ------------    ---------
00000000    003FFFFF    00400000    Flash Image

00000000    00000FFF    00001000    Descriptor Region
00000004    0000000F    0000000C        Descriptor Map
00000010    0000001B    0000000C        Component Section
00000040    0000004F    00000010        Region Section
00000060    0000006B    0000000C        Master Access Section
00000060    00000063    00000004            CPU/BIOS
00000064    00000067    00000004            Manageability Engine (ME)
00000068    0000006B    00000004            GbE LAN
00000100    00000103    00000004        ICH Strap 0
00000104    00000107    00000004        ICH Strap 1
00000200    00000203    00000004        MCH Strap 0
00000ED0    00000EF7    00000028        ME VSCC Table
00000ED0    00000ED7    00000008            Flash device 1
00000ED8    00000EDF    00000008            Flash device 2
00000EE0    00000EE7    00000008            Flash device 3
00000EE8    00000EEF    00000008            Flash device 4
00000EF0    00000EF7    00000008            Flash device 5
00000EFC    00000EFF    00000004        Descriptor Map 2
00000F00    00000FFF    00000100        OEM Section
00001000    00002FFF    00002000    GbE Region
00003000    00202FFF    00200000    BIOS Region

Build Settings
--------------
Flash Erase Size = 0x1000

It’s a utility called ‘Flash Image Tool’ for ME 4.x that was used for this. You drag a complete image into in and the utility decomposes the various components, allowing you to set soft straps.

This tool is proprietary, for Windows only, but was used to deblob the X200. End justified means, and the utility is no longer needed since the ich9deblob utility (documented on this page) can now be used to create deblobbed descriptors.

GBE (gigabit ethernet) region in SPI flash

Of the 8K, about 95% is 0xFF. The data is the gbe region is fully documented in this public datasheet: http://www.intel.co.uk/content/dam/doc/application-note/i-o-controller-hub-9m-82567lf-lm-v-nvm-map-appl-note.pdf

The only actual content found was:

00  1F  1F  1F  1F  1F  00  08  FF  FF  83  10  FF  FF  FF  FF  
08  10  FF  FF  C3  10  EE  20  AA  17  F5  10  86  80  00  00  
01  0D  00  00  00  00  05  06  20  30  00  0A  00  00  8B  8D  
02  06  40  2B  43  00  00  00  F5  10  AD  BA  F5  10  BF  10  
AD  BA  CB  10  AD  BA  AD  BA  00  00  00  00  00  00  00  00  
00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  00  
00  01  00  40  28  12  07  40  FF  FF  FF  FF  FF  FF  FF  FF  
FF  FF  FF  FF  FF  FF  FF  FF  FF  FF  FF  FF  FF  FF  D9  F0  
20  60  1F  00  02  00  13  00  00  80  1D  00  FF  00  16  00  
DD  CC  18  00  11  20  17  00  DD  DD  18  00  12  20  17  00  
00  80  1D  00  00  00  1F  

The first part is the MAC address set to all 0x1F. It’s repeated haly way through the 8K area, and the rest is all 0xFF. This is all documented in the datasheet.

The GBe region starts at 0x20A000 bytes from the *end* of a factory image and is 0x2000 bytes long. In Libreboot (deblobbed) the descriptor is set to put gbe directly after the initial 4K flash descriptor. So the first 4K of the ROM is the descriptor, and then the next 8K is the gbe region.

GBE region: change MAC address

According to the datasheet, it’s supposed to add up to 0xBABA but can actually be others on the X200. https://web.archive.org/web/20150912070329/https://communities.intel.com/community/wired/blog/2010/10/14/how-to-basic-eeprom-checksums

“One of those engineers loves classic rock music, so they selected 0xBABA”

In honour of the song Baba O’Reilly by The Who apparently. We’re not making this stuff up…

0x3ABA, 0x34BA, 0x40BA and more have been observed in the main Gbe regions on the X200 factory.rom dumps. The checksums of the backup regions match BABA, however. We think 0xBABA is the only correct checksum, because those other, similar checksums were only ever found in the “backup” GbE regions on factory ROM dumps. In Libreboot, we simply use 0xBABA and ensure that both 4KiB regions in GbE NVM have that checksum.

By default, the X200 (as shipped by Lenovo) actually has an invalid main gbe checksum. The backup gbe region is correct, and is what these systems default to. Basically, you should do what you need on the *backup* gbe region, and then correct the main one by copying from the backup.

Look at ich9deblob.c in ich9utils.

Flash descriptor region

http://www.intel.co.uk/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf from page 850 onwards. This explains everything that is in the flash descriptor, which can be used to understand what Libreboot is doing about modifying it.

How to deblob:

There’s an interesting parameter called ‘ME Alternate disable’, which allows the ME to only handle hardware errata in the southbridge, but disables any other functionality. This is similar to the ‘ignition’ in the 5 series and higher but using the standard firmware instead of a small 128K version. Useless for Libreboot, though.

To deblob GM45, you chop out the platform and ME regions and correct the addresses in flReg1-4. Then you set meDisable to 1 in ICHSTRAP0 and MCHSTRAP0.

How to patch the descriptor from the factory.rom dump

This means that Libreboot’s descriptor region will simply define the following regions:

The data in the descriptor region is little endian, and it represents bits 24:12 of the address (bits 12-24, written this way since bit 24 is nearer to left than bit 12 in the binary representation).

So, x << 12 = address

If it’s in descriptor mode, then the first 4 bytes will be 5A A5 F0 0F.

platform data partition in boot flash (factory.rom / lenovo bios)

Basically useless for Libreboot, since it appears to be a blob. Removing it didn’t cause any issues in Libreboot. We think it’s just random data that the manufacturer can put there, to use in their firmware. Intel datasheets seem to suggest that the platform region serves no specific function except to provide a region in flash for the hardware manufacturer to use, for whatever purpose (probably just to store other configuration data, to be used by software running from the BIOS region as per region layout specified in the descriptor).

This is a 32K region from the factory image. It could be data (non-functional) that the original Lenovo BIOS used, but we don’t know.

It has only a 448 byte fragment different from 0x00 or 0xFF, on the X200 thinkpads that were tested.

Markdown file for this page: https://libreboot.org/docs/install/ich9utils.md

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