this post was submitted on 11 Jun 2023
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Libreboot

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I'm aware that Leah strongly discourages using CH341a, but I understand that this is chiefly because it's voltage is 5V, whiich risks burning the 1.8V or 3.3V datalines of the devices we're librebooting.

At the same time, I've seen a popular video specifically recommending CH341a when librebooting an X200. I assume this advice should be ignored.

However, Leah also specifies that you can technically tweak the CH341a to reduce it's voltage, following this guidance.

My question is: is this worth it, or is it safer to just use a Beaglebone Black/Raspbery Pi instead? What's your experience been?

I'm unfortunately on a budget, and BB/RPi are both prohibitively expensive for me. Then again, so is a laptop that's bricked thanks to an improperly fixed CH341a.

Have you had problems using a (tweaked or untweaked) CH341a? What's your advice? I really appreciate it. Thanks!

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[–] [email protected] 2 points 1 year ago (1 children)

Never on X200, but I've tested this on X230, X60, and W530. It all works.

Perhaps measure the voltage if you really wanna be careful. If you're lazy, you can test by getting a similar flash chip and flashing it.

Extra tip: you can use Arduino as external power.

[–] [email protected] 1 points 1 year ago (1 children)

Thanks a ton. I've been looking into this myself, and it seems like the issue was mostly due to a few faulty CH341a models, and it also seems that newer models allow a toggle between 3.3v and 5v. But reassuring that it's worked well for you too.

I think I might get a cheap multimeter as they can come for less than $10, just to be safe. Could be a good long term investment!

[–] [email protected] 1 points 1 year ago (1 children)

Are you saying that you got multiple faulty CH341a?

I did ran into an issue of inconsistent chip reading and the issue turned out to be the lack of amps. For that I attached an external power supply. Arduino works as long as the AC plug is used (not the USB).

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

Oh sorry I meant I've seen reports that the voltage issue was due to a few faulty programmers, I've personally never used one.

Interestingly, this video also brings up amps as the root cause, not volts. I might get an Arduino in that case just for more control, but would you say it's beginner-friendly? This would be my first time attempting libreboot (or any kind of chip programming for that matter)..

[–] [email protected] 1 points 1 year ago

You'd only need to plug the power in and connect the 3v3 & ground to the chip. I was only mentioning this because then you'd never have to set the voltage and a lot of people have it laying around. Otherwise, any DC power supply would do as long as you can get that 3.3v output.

[–] [email protected] 2 points 1 year ago

I've had zero luck with external flashing. I've tried the CH341A programmer and a Raspberry Pi to flash an X200, haven't gotten it to work. If you're referring to the Wolfgang video, I followed that video as close as I could, but it didn't work.

[–] [email protected] 1 points 1 year ago

I don't have any experience with that but what I can tell you, you can build a voltage divider for using 2 resistors. So that's definitely possible on a budget m

This is a handy calculator https://ohmslawcalculator.com/voltage-divider-calculator which you use to plugin the input and the desired output voltage. I hope that helps!

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