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Fix T480s-maximized.md: apply PR #218 content with review-identified corrections #220

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Fix review comments on T480s-maximized.md from PR #218
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Fix T480s-maximized.md: address all review comments
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129 changes: 68 additions & 61 deletions Installing-and-Configuring/Flashing-Guides/T480s-maximized.md
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Original file line number Diff line number Diff line change
Expand Up @@ -22,9 +22,10 @@ For whole procedure you will need:
- Other laptop/PC with a Linux-based OS installed.
- Optional: A plastic guitar pick or an old credit card to help detach the bottom case from the clips holding it in place. Otherwise, it can be difficult to remove, increasing the risk of breaking the tabs or the top part of the bottom case above the battery connector.

There is still debate over which programmer and software should be used (flashprog vs. flashrom). Before following this guide, make sure you read [README.md](https://github.com/linuxboot/heads/tree/master/blobs/xx80/README.md) and the related information.
There is still debate over which programmer and software should be used (flashprog vs. flashrom); however, this guide uses flashrom to keep all the steps consistent.
Before following this guide, make sure you read [README.md](https://github.com/linuxboot/heads/tree/master/blobs/xx80/README.md) and the related information.

Some ThinkPad T480s units on the used market, like the T480, are affected by an Intel bug in the Thunderbolt firmware. In short, the flash chip becomes full, causing Thunderbolt fast charging to stop working, though slow charging still functions. This issue can also affect the USB-C port. For convenience, Heads provides a fixed and padded Thunderbolt firmware that resolves the "charging problem" if your laptop is affected. Board testers did not encounter this issue, and it is unlikely to occur if your laptop was in use for more than 12 months before flashing. If you do experience the "charging bug," it is possible to fix it with external flashing. Also, the update is possible prior flashing heads using [fwupd from a Linux distribution](https://www.reddit.com/r/thinkpad/comments/12tf6xv/psa_t480_thunderbolt_controller_v23_is_now_on/)
Some ThinkPad T480s units on the used market are affected by an Intel bug in the Thunderbolt firmware. In short, the flash chip becomes full, causing Thunderbolt fast charging to stop working, though slow charging still functions. This issue can also affect the USB-C port. For convenience, Heads provides a fixed and padded Thunderbolt firmware that resolves the "charging problem" if your laptop is affected. Board testers did not encounter this issue, and it is unlikely to occur if your laptop was in use for more than 12 months before flashing. If you do experience the "charging bug," it is possible to fix it with external flashing. Also, the update is possible prior to flashing Heads by using [fwupd from a Linux distribution](https://www.reddit.com/r/thinkpad/comments/12tf6xv/psa_t480_thunderbolt_controller_v23_is_now_on/).

Please note that as of March 2025, Thunderbolt data transfer is not supported upstream by [coreboot](https://review.coreboot.org/c/coreboot/+/83274). However, video output through Thunderbolt and charging still work. This means only the USB-C charging port can be used for data transfer.

Expand Down Expand Up @@ -81,70 +82,50 @@ Try to read the name of the SPI flash chip. The dot on the chip helps to identif

![SPI BIOS flash chip closed view]({{ site.baseurl }}/images/T480s/4_bios_chip_orientation.jpg)

First, connect the clip of your chosen SPI programmer (Raspberry Pi Pico was used in the sample commands) to the chip. Next, connect the programmer to the USB port of your other Linux-based computer with flashrom installed. In my setup, the red wire should be where the dot is (the dot indicates pin 1). Here, please also see the flashing guide for the T430.
First, connect the clip of your chosen SPI programmer (CH341A Programmer was used here) to the chip. Next, connect the programmer to the USB port of your other Linux-based computer with flashrom installed. In my setup, the red wire should be where the dot is (the dot indicates pin 1). Here, please also see the [flashing guide for the T480]({{ site.baseurl }}/T480-maximized-flashing/).

Use flashrom/flashprog to check the chip you are connected to:
Use flashrom to check the chip you are connected to:

```shell
sudo flashprog -p serprog:dev=/dev/ttyACM0:spispeed=16M
sudo flashrom --programmer [programmer]
```

Here is my output.

```
flashprog p1.3-2-geb2c041 on Linux 6.12.21-1.qubes.fc37.x86_64 (x86_64)
flashprog is free software, get the source code at https://flashprog.org
flashrom v1.6.0 on Linux 6.19.14+kali-amd64 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
serprog: Programmer name is "pico-serprog"
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on serprog.
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on ch341a_spi.
No operations were specified.
```

Read from the chip twice (where the name of the flash chip is `YYY`):
Read from the chip twice to make sure our original BIOS file is consistent (where the name of the flash chip is `YYY`):

```shell
sudo flashprog -r ~/t480s_original_bios.bin --programmer serprog:dev=/dev/ttyACM0:spispeed=16M -c YYY
sudo flashrom --programmer [programmer] --read ~/t480s_original_bios.bin --chip YYY
```

First output can be seen here.

It will then dump our original BIOS prior to flashing Heads to:
```
flashprog p1.3-2-geb2c041 on Linux 6.12.21-1.qubes.fc37.x86_64 (x86_64)
flashprog is free software, get the source code at https://flashprog.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
serprog: Programmer name is "pico-serprog"
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on serprog.
Reading flash... done.
~/t480s_original_bios.bin
```


And do it once again just to make sure (notice a different file name is used below):
```shell
sudo flashprog -r ~/t480s_original_bios_1.bin --programmer serprog:dev=/dev/ttyACM0:spispeed=16M -c YYY
sudo flashrom --programmer [programmer] --read ~/t480s_original_bios_1.bin --chip YYY
```
Second output can be seen here.

It will then dump our original BIOS (second read attempt) prior to flashing Heads to:
```
flashprog p1.3-2-geb2c041 on Linux 6.12.21-1.qubes.fc37.x86_64 (x86_64)
flashprog is free software, get the source code at https://flashprog.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
serprog: Programmer name is "pico-serprog"
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on serprog.
Reading flash... done.
~/t480s_original_bios_1.bin
```

Make sure that the dump matches the chip content. If this is the case, the output of the following command will state `Verifying flash... VERIFIED`

```shell
sudo flashprog -v ~/t480_original_bios.bin --programmer serprog:dev=/dev/ttyACM0:spispeed=16M -c YYY
```
Make sure that files do not differ.
Make sure that files do not differ. We can verify them using `sha256sum` as follows:

```shell
sha256sum t480s_original_bios.bin
sha256sum t480s_original_bios_1.bin
sha256sum ~/t480s_original_bios.bin
sha256sum ~/t480s_original_bios_1.bin
```

My dumps were the same.
Expand All @@ -159,33 +140,45 @@ My dumps were the same.
Alternative comparison is bit-by-bit. If the files are the same, there should be no output of this command. Otherwise, you will see a bit-by-bit difference between the files.

```shell
diff <(hexdump -C t480s_original_bios.bin) <(hexdump -C t480s_original_bios_1.bin)
diff <(hexdump -C ~/t480s_original_bios.bin) <(hexdump -C ~/t480s_original_bios_1.bin)
```

If the files differ or the chip content does not match the dump, try reconnecting your programmer to the SPI flash chip and make sure your flashrom/flashprog software is up-to-date.
Now make sure that the dump matches the chip content. If this is the case, the output of the following command will state `Verifying flash... VERIFIED`
```shell
sudo flashrom --programmer [programmer] --verify ~/t480s_original_bios.bin --chip YYY
```

In our case the command output is:
```
flashrom v1.6.0 on Linux 6.19.14+kali-amd64 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

If they are the same, then write `t480s-hotp-maximized.rom` to the SPI flash chip:
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on ch341a_spi.
Verifying flash... VERIFIED.
```

If the files differ or the chip content does not match the dump, try reconnecting your programmer to the SPI flash chip and make sure your flashrom software is up-to-date.


If they are the same, then write `t480s-maximized.rom` to the SPI flash chip:

```shell
sudo flashprog -p serprog:dev=/dev/ttyACM0:spispeed=16M -c YYY -w ~/heads/build/x86/t480s-hotp-maximized/heads-t480s-hotp-maximized.rom
sudo flashrom --programmer [programmer] --chip YYY --write t480s-maximized.rom
```

Here is a successful attempt. Be patient, it may take a while.

```
flashprog p1.3-2-geb2c041 on Linux 6.12.21-1.qubes.fc37.x86_64 (x86_64)
flashprog is free software, get the source code at https://flashprog.org
flashrom v1.6.0 on Linux 6.19.14+kali-amd64 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
serprog: Programmer name is "pico-serprog"
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on serprog.
Found Winbond flash chip "W25Q128.V" (16384 kB, SPI) on ch341a_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Updating flash chip contents... Erase/write done from 0 to ffffff
Verifying flash... VERIFIED.
```

If all goes, well you can connect the CMOS and internal battery, press the power button and you should see the keyboard LED flash. After that, Heads will boot into its GUI.
If all goes well, you can connect the CMOS and internal battery, press the power button and you should see the keyboard LED flash. After that, Heads will boot into its GUI.

Two reboots are sometimes needed after flashing. Force a power off by holding the power button for 10 seconds. Since the memory training data was wiped by the content of the fully flashed ROM, this is normal.

Expand All @@ -196,19 +189,29 @@ Important, ensure that power supply and all batteries, including the CMOS batter

Check the chip you are connected to:
```shell
sudo flashprog -p serprog:dev=/dev/ttyACM0:spispeed=16M
sudo flashrom --programmer [programmer]
```
Output:
```
flashprog p1.3-2-geb2c041 on Linux 6.12.21-1.qubes.fc37.x86_64 (x86_64)
flashprog is free software, get the source code at https://flashprog.org
flashrom v1.6.0 on Linux 6.19.14+kali-amd64 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
serprog: Programmer name is "pico-serprog"
Found Winbond flash chip "W25Q80.V" (1024 kB, SPI) on serprog.
Found Winbond flash chip "W25Q80.V" (1024 kB, SPI) on ch341a_spi.
===
This flash part has status UNTESTED for operations: WP
The test status of this chip may have been updated in the latest development
version of flashrom. If you are running the latest development version,
please email a report to flashrom@flashrom.org if any of the above operations
work correctly for you with this flash chip. Please include the flashrom log
file for all operations you tested (see the man page for details), and mention
which mainboard or programmer you tested in the subject line.
You can also try to follow the instructions here:
https://www.flashrom.org/contrib_howtos/how_to_mark_chip_tested.html
Thanks for your help!
No operations were specified.
```

Dump the Thunderbolt firmware (again, twice, and compare):
```shell
sudo flashrom --programmer [programmer] --read ~/t480s_original_tb.bin --chip YYY
```
Expand All @@ -217,20 +220,24 @@ sudo flashrom --programmer [programmer] --read ~/t480s_original_tb.bin --chip YY
sudo flashrom --programmer [programmer] --read ~/t480s_original_tb_1.bin --chip YYY
```

Compare our Thunderbolt firmware dumps with `sha256sum`:
```shell
sudo flashrom --programmer [programmer] --verify ~/t480s_original_tb.bin --chip YYY
sha256sum ~/t480s_original_tb.bin
sha256sum ~/t480s_original_tb_1.bin
```

Or, bit-by-bit with `diff`
```shell
sha256sum t480s_original_tb.bin
sha256sum t480s_original_tb_1.bin
diff <(hexdump -C ~/t480s_original_tb.bin) <(hexdump -C ~/t480s_original_tb_1.bin)
```

And if they match, proceed to verify the flash:

```shell
diff <(hexdump -C t480_original_tb.bin) <(hexdump -C t480_original_tb_1.bin)
sudo flashrom --programmer [programmer] --verify ~/t480s_original_tb.bin --chip YYY
```

Flash the padded Thunderbolt firmware. The firmware file tb.bin is located in the blobs folder after you build the Heads locally, or in the CircleCI artifacts.
Flash the padded Thunderbolt firmware. The firmware file t480s_tb.bin is located in the blobs folder after you build the Heads locally, or in the CircleCI artifacts.

```shell
sudo flashrom --programmer [programmer] --chip YYY --write ~/t480s_tb.bin
Expand Down