Group:Hardware/RepairsRefurbishingAndMaintenance

Introduction

This page is meant to list free software applications or code that can be used to either:

• Repair devices
• Do regular device maintenance to keep the devices functional
• Repurpose devices

Software for specific hardware

Batteries

Linux /sys/class/power_supply/*/

X86 Laptops batteries often have a nonfree firmware somewhere and calibration data. The computer embedded controller usually interfaces with that firmware. And Linux has drivers to talk to the embedded controller to get data about the battery used by laptops.

We can usually get battery information through Linux standard interfaces:

$ grep . /sys/class/power_supply/BAT0/uevent 
POWER_SUPPLY_NAME=BAT0
POWER_SUPPLY_TYPE=Battery
POWER_SUPPLY_STATUS=Discharging
POWER_SUPPLY_PRESENT=1
[...]
POWER_SUPPLY_POWER_NOW=15191000
POWER_SUPPLY_ENERGY_FULL_DESIGN=84240000
POWER_SUPPLY_ENERGY_FULL=32310000
POWER_SUPPLY_ENERGY_NOW=9690000
POWER_SUPPLY_CAPACITY=29
POWER_SUPPLY_CAPACITY_LEVEL=Normal
[...]

So not only we can see if charging works (here it's Discharging) but in a lot of cases, we can even understand how much the battery would last compared to the amount of time it lasted when manufactured.

Here we can simply calculate that by dividing POWER_SUPPLY_ENERGY_FULL by POWER_SUPPLY_ENERGY_FULL_DESIGN:

$ python3
Python 3.9.9 (main, Jan  1 1970, 00:00:01) 
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 100 * (32310000 / 84240000)
38.35470085470086

Note that this information is only accurate if the calibration data is correct. Batteries typically have I2C interfaces, so it's possible to talk to the battery firmware and it's probably possible to modify its calibration data too in some way.

So the battery I'm using will last 38% of the original battery. So if the battery lasted 5 hours after being manufactured, it will now last about 1 hours and 55 minutes.

In contrast with x86 laptops smartphones also have calibration data (typically in the battery gauge chip), but they often don't have any information on how much the battery would last compared to the original battery life.

A way to find out could be to develop a procedure that drains the battery as fast as possible (for instance using cpuburn to use the CPU as much as possible) and look how much different batteries last.

It might also be possible to caracterize the battery directly with hardware meant to discharge it and measure its voltage with multimeters and sigrok (a free software tool that can retrieve information from some multimeters).

Cooling

cpuburn

The cpuburn software tries to use a CPU core as much as possible so that can be used to test the cooling of a device, or the CPUs. If you have 8 cores, you need to run 8 instances of that software.

Implementations exists for multiple CPU for at least ARM and x86.

Linux

• Linux has an hwmon subsystem and it can be used to manually control fans
• Linux can also report various temperature sensors data through the hwmon subsystem

lm_sensors

lm_sensors can use data exported by Linux to print temperatures etc

Ethernet controllers

Ethtool and Linux drivers

Some ethernet controller have some (usually I2C) flash chip used to hold their configuration data.

Sometimes the content of this chip is corrupted, making the Ethernet controller useless (for instance because the driver refuses to load.

For some e1000 or e1000e compatible controllers, it's possible to patch Linux to make sure that the driver loads, and then use ethtool to reprogram the flash chip.

For that to work, the flash chip needs to be directly connected to the Ethernet controller. This is the case with computers like the Thinkpad X60.

Flashrom, bincfg, ich9gen and ifdtool

On some computers (like the Thinkpad X200), the Ethernet controller configuration data is not on a dedicated flash chip, but it's in a partition of the flash chip that also holds the BIOS.

For that, flashrom can be used to dump the flash chip content (that can usually be done on the laptop itself if it runs Libreboot or Coreboot).

Once this is done, ifdtool (which is available in Parabola in the libreboot-utils package) can extract the content of the Ethernet controller partition.

Its content can either be recreated with Libreboot's ich9gen, or with bincfg (part of libreboot-utils in Parabola).

The ich9gen tool is way easier to use as it only asks the MAC address on the command line:

ich9gen --macaddress XX:XX:XX:XX:XX:XX

the mac address is often found on a sticker on the bottom of the laptop. The ich9gen tool then produces a file that has the intel flash descriptor (the partition table of the flash chip) and the Ethernet controller partition. The later can be extracted with ifdtool again, for instance with

ifdtool -x ich9fdgbe_8m.bin

The bincfg tool can instead edit all the configuration of the Ethernet controller partition, but it requires users to download the datasheet (easily found online and/or on the Intel website) and to understand each field to modify. So it's way harder to use.

Flash chips

Flashrom

Flashrom can read and write various flash chips (With Parallel, SPI, FWH, LPC interfaces) so it can potentially be used to repair many devices. You also need a compatible flash programmer (that works with a compatible voltage level) to program flash chips conveniently.

On some computers it can also read/write the computer flash chip that holds the boot software (like the BIOS or UEFI). It can also read/write the flash chip of various cards (like GPUs, network cards, etc). In both cases it's not always able to read/write the full flash chip as sometimes the hardware configuration can prevent that (in case of laptops for instance), and other times the code is not stable enough to write the flash chip (for some GPUs and/or network cards).

Website: https://www.flashrom.org/

Linux + flashrom or mtd-utils

Linux can also read various flash chips. For instance you might be able to use a single board computer that runs GNU/Linux and connect a flash chip to it, modify the device tree to take it into account, and use the Linux driver along with mtd-utils or flashrom with the linux_mtd driver to read/write it.

Another option would be to only enable the SPI bus that has the flash chip in the device tree and use then use flashrom to read/write it through flashrom's linux_spi driver.

GPUs

Games

Various free software 3D games can be used to test GPUs.

Some games need a big quantity of RAM to run (Xonotic and supertuxkart probably require 2GiB of RAM or more for instance).

Many old computers cannot have that much RAM (due to chipset limitations). Even some modern computers have soldered RAM, so in that case RAM can't easily be increased either.

For cases like that, extreme Tux racer uses 3D acceleration and don't require a big quantity of RAM, so it could be used to test GPUs on such computers. It is available in several FSDG compliant distributions like Parabola and Guix.

Phoronix test suite

Phoronix test suite can also be used to test GPUs. Note that by default many tests are nonfree.

Both Guix and Parabola's phoronix-test-suite have free tests.

The Guix version is probably more advanced as Parabola's version is old and lack games (it's limited to compilation tests), at least until volunteers fix that in Parabola.

Flashrom and sgabios

Some broken GPUs can probably be repurposed with flashrom and sgabios.

Sgabios can be used to redirect the output of the computer in the BIOS on a serial port. This could be useful to people with visual deficiencies or for people administrating servers.

Reprogramming the flash chip of modern GPUs might need to be done with flashrom and an external programmer (because flashrom doesn't have support for recent ATI or AMD GPUs).

HDDs and SSDs

Gnome disks

Gnome disks can test HDDs and SSDs to see if they are broken or not.

Website: https://apps.gnome.org/en/app/org.gnome.DiskUtility/

smartmontools

Smartmontools can test HDDs and SSD to see if they are broken or not.

Website: http://smartmontools.sourceforge.net

Flashrom

Flashrom can also be used to dump and restore some HDDs and SSDs firmwares as the flash chips holding the firmwares are often easily accessible on the hard disk PCB.

Debug interface

Sometimes there is a debug interface on HDDs and SSDs. An UART connection can be used to interact with it. Note that using that is very dangerous as you can easily loose data.

TODO: find the talk about it.

hdparm

TODO: find if there are information about repairing or repurposing hard disks with hdparm.

NAND reader

There is hardware schematics and GPLv3(+?) software for a NAND reader that available here: https://spritesmods.com/?art=ftdinand

That might be useful to recover data from an SSD (SSDs use NAND).

There will probably be data used by the SSD firmware as well on the NAND, like checksums for the data being written, bad block information, or block usage information, etc.

So we would probbaly need to reverse engineer to recover the data.

Modems

simtrace and simtrace2

Simtrace and Simtrace2 can trace the communication between a SIM card and a mode. Thanks to that it is possible to gain some information on what is going on, for instance:

• If the screen is broken we might see some acvitivy through that
• It might be useful to debug a SIM card reported as not found: if there is some traffic, the modem sees the SIM card

Osmocom GSM stack

It might be possible to use OpenBSC and so on to emulate a GSM network to see if a phone is working well, however the hardware to do that is probably expensive.

In addition it would require special cables between the phone and the GSM network to ensure that the GSM network doesn't emit ouside of the cable (to not require a (test) license).

network manager / modem manager / oFono etc

The various GNU/linux modem stacks can obviously be used to test some modems.

The test suites of these modem stacks or network test suites like Titan_TTCN3_Testsuites might be able to be repurposed to run automatic tests.

RAM

Memtest86+

Memtest86+ is an application that can be launched in GRUB and that can test the RAM.

For that to work the computer needs to be able to boot up to GRUB so if the RAM module under test is very broken, you might have more luck with two RAM modules: one good and the one under test.

Libreboot or Coreboot on Libreboot supported devices

Libreboot supports laptops with DDR2 (I945) and DDR3 (GM45).

It also supports some desktop computers.

If one hook up a serial port (on compatible computers, through the dock) it is possible to get some diagnostics even if the RAM isn't working at all.

They also has a fork of Memtest86+ that works over an UART.

Coreboot on Libreboot supported devices

On some of these computers the RAM initialization isn't free software so it might not give much information on what is going wrong. Note that Coreboot contains nonfree software. That is why Libreboot was made in the first place. Libreboot contains script to produce deblobed versions of Coreboot. Some vendors selling RYF certified hardware have also released deblobbed Coreboot as part of their RYF certification.

Novena + u-boot

The novena laptop also has slots for RAM modules and in u-boot, the RAM intialization code for that laptop is free software. Though u-boot itself might need to be deblobbed as some of its versions contain nonfree software (like nonfree firmwares and/or binaries under nonfree licenses).

Parabola has already some packages for some computers using an I.MX6 system on a chip, so it might be possible to ask Parabola developers to add support for the novena if you accept to test the resulting package.

Software for characterizing hardware

People dealing with refurbishing hardware often need to know what's inside the computer. There are many free software projects that can find hardware inside computers.

h-client

The h-client program can be useful to not only find what's in the computer, but it can even send information about what works and what doesn't (with 100% free software distributions) to h-node.

It can be installed in Guix, so it's even possible to make a special Guix image (to be installed on an USB key) or to make a Debian package (with guix) to install it on top of 100% free software distributions.

Note that h-node only accepts information if the computer is being tested on 100% free distributions (that includes all FSDG compliant distributions, obviously with no additional nonfree software, and Debian with only the main repository and no additional nonfree software)

lshw

The lshw program can not only list what hardware is in the computer it's running on, but it can also output that information in a wide variety of format, like for instance json or even in an sqlite database.

That makes it easy to reuse that data in a more global system that tracks what hardware there is in the organization that refurbish hardware.

Inventory software

There is several free software inventory programs (like OCS Inventory for instance). Some are pretty well adapted to large organizations.

Something to look for would be to understand the level of details needed and see if it fit well what organization that refurbish hardware need.

Software for general purpose debug and repair tools

Sigrok

Sigrok can interface with a wide variety of hardware like:

• Digital analyzers
• Multimeters
• Osciloscopes
• Power supplies
• etc

So it can be super useful for debugging hardware issues.