[coreboot] T520 vs. T530

[y***@hs-weingarten.de]

Hello guys,

I am planning to buy a used Lenovo Thinkpad and install coreboot on it. I am completely new to coreboot and I need help in the decision if I should buy a T520 or a T530. I read the wiki and some other pages but it's still hard for me to decide which model I should buy.

1. I need CPU power. I read that it is possible to put a i7-3940XM in a T530. Because of coreboot it should also possible to put it in a T520?

2. I would like to use an eGPU. Any differences between these two models?

3. With which model it is easier to install coreboot on it?

4. What are the general pros and cons of a T520/T530, especially with coreboot?

Thanks for your help!
Kind regards

[Iru Cai]

The iGPU T520 and dGPU T420 have stability problems when running coreboot. (
https://ticket.coreboot.org/issues/121)
So get a T530/W530/W520/dGPU T520.

I don't know the eGPU status of notebooks running coreboot.

Post by y***@hs-weingarten.de
Hello guys,
I am planning to buy a used Lenovo Thinkpad and install coreboot on it. I
am completely new to coreboot and I need help in the decision if I should
buy a T520 or a T530. I read the wiki and some other pages but it's still
hard for me to decide which model I should buy.
1. I need CPU power. I read that it is possible to put a i7-3940XM in a
T530. Because of coreboot it should also possible to put it in a T520?
2. I would like to use an eGPU. Any differences between these two models?
3. With which model it is easier to install coreboot on it?
4. What are the general pros and cons of a T520/T530, especially with coreboot?
Thanks for your help!
Kind regards--
https://mail.coreboot.org/mailman/listinfo/coreboot

[Michał Kopeć]

Post by y***@hs-weingarten.de
1. I need CPU power. I read that it is possible to put a i7-3940XM in a T530. Because of coreboot it should also possible to put it in a T520?

Yes, with Coreboot you can put an Ivy Bridge CPU into a xx20 series ThinkPads.

Post by y***@hs-weingarten.de
2. I would like to use an eGPU. Any differences between these two models?

Not really, especially with coreboot. I'm glad to report that my RX
580 eGPU works well with my T430 running Coreboot - just make sure you
enable ONBOARD_VGA_IS_PRIMARY in your config, otherwise your
integrated graphics will be disabled and you'll lose eGPU hotplug.

Post by y***@hs-weingarten.de
3. With which model it is easier to install coreboot on it?

No practical difference, the building and flashing procedure is the same.

Post by y***@hs-weingarten.de
4. What are the general pros and cons of a T520/T530, especially with coreboot?

T530 will not accept non-Lenovo batteries unlesh you flash a patched
EC firmware, and that can only be done while you're still running
stock UEFI. T530 has USB 3.0, T520 has a keyboard that some consider
superior. Otherwise the machines are extremely similar.

[Evgeny Zinoviev]

Post by Michał Kopeć

Post by y***@hs-weingarten.de
3. With which model it is easier to install coreboot on it?

No practical difference, the building and flashing procedure is the same.

Not quite so. On T520 the flash chip is accessible right after you
remove the keyboard and the palmrest and there's no need to remove the
motherboard from chassis. On T530 there are two flash chips and while
the 8M one is easily accessible after you remove the palmrest, the 4M
one is covered with the magnesium frame and you have to disassemble the
laptop completely, and the 4M one is the one you need to flash. Although
it's possible to use just the 8M chip by using modified layout, it might
be confusing for a beginner. (I wrote a guide how to do that based on my
W530 experience, here:
https://www.reddit.com/r/coreboot/comments/956ymu/howto_flash_coreboot_on_x230t430t530w530_using/)

[Nico Huber]

Post by Michał Kopeć

Post by y***@hs-weingarten.de
1. I need CPU power. I read that it is possible to put a i7-3940XM in a
T530. Because of coreboot it should also possible to put it in a T520?

Yes, with Coreboot you can put an Ivy Bridge CPU into a xx20 series ThinkPads.

It works sometimes. AFAIK, nobody has figured out yet which combinations
work and which don't. Might depend on the processor stepping, the ME
firmware version, DRAM clock etc.

Though, with some patience you'd likely get it to work.

Post by Michał Kopeć

Post by y***@hs-weingarten.de
3. With which model it is easier to install coreboot on it?

No practical difference, the building and flashing procedure is the same.

Actually, there are many differences, IIRC. The T520 has a single flash
chip. The T530 has two. And, AFAIK, the T530 lacks pull-ups on the flash
chips' /CS signals. Which means you have to connect both chips' /CS pins
appropriately to access any of them.

Post by Michał Kopeć

Post by y***@hs-weingarten.de
4. What are the general pros and cons of a T520/T530, especially with coreboot?

T530 will not accept non-Lenovo batteries unlesh you flash a patched
EC firmware, and that can only be done while you're still running
stock UEFI. T530 has USB 3.0, T520 has a keyboard that some consider
superior. Otherwise the machines are extremely similar.

The initialization of the T530's USB 3.0 controller is incomplete. You
could use a reference-code blob though (or use the blob's results to
fill the gaps in the initialization routine).

Nico

[Michał Kopeć]

Post by Evgeny Zinoviev
Not quite so. On T520 the flash chip is accessible right after you
remove the keyboard and the palmrest and there's no need to remove the
motherboard from chassis.

Sorry, my bad. I mixed up my facts there.

Post by Evgeny Zinoviev
Although it's possible to use just the 8M chip by using modified layout, it might
be confusing for a beginner.

I managed to flash my T430's both flash chips by splitting the 12M
coreboot image into two parts (4M + 8M) and flashing the chips
separately, is this not a good option?
This way I don't have to pass a layout file to flashrom, it just
writes to both chips. It also allows me to have a larger CBFS.

[Evgeny Zinoviev]

Post by Michał Kopeć

Post by Evgeny Zinoviev
Although it's possible to use just the 8M chip by using modified layout, it might
be confusing for a beginner.

I managed to flash my T430's both flash chips by splitting the 12M
coreboot image into two parts (4M + 8M) and flashing the chips
separately, is this not a good option?
This way I don't have to pass a layout file to flashrom, it just
writes to both chips. It also allows me to have a larger CBFS.

See, already confusing ;)
 
On T530/W530 you can access the 8M chip right after you remove the
keyboard and palmrest, but the 4M chip stays under the frame. And if you
don't want to waste your time by disassembling the laptop completely and
then assembling it back, you can use only the 8M chip and never even
touch the 4M one, but in order to do that, you have to modify the layout.

[Nico Huber]

Post by Michał Kopeć

Post by Evgeny Zinoviev
Not quite so. On T520 the flash chip is accessible right after you
remove the keyboard and the palmrest and there's no need to remove the
motherboard from chassis.

Sorry, my bad. I mixed up my facts there.

Post by Evgeny Zinoviev
Although it's possible to use just the 8M chip by using modified layout, it might
be confusing for a beginner.

I managed to flash my T430's both flash chips by splitting the 12M
coreboot image into two parts (4M + 8M) and flashing the chips
separately, is this not a good option?

It depends heavily on what you want to accomplish. For instance if you
just want to install coreboot (no ME tampering) and can live with up to
7MiB for CBFS, you don't have to touch the 8MiB ever externally.

Nico