I need to clear out these doubts of mine.
Is the motherboard battery necessary for the computer to power on?
If it turns on without a battery, is it harmful to use the computer without a battery?
I'm building a mini laptop (Intel Learning Series, EF10MI2), and I buy the pieces from a "tech guy".
I only needed 2 things for the laptop to turn on; RAM and "side board".
I told a friend of mine and he gifted me these 2 pieces.
I installed the necessary hardware for the laptop to power on, I tried to turn it on and nothing happens, it won't even show the LED when I connect the charger.
Days later I told my friend, he said it could be the battery (The big one) or the "side board", as we call it here (It's the board that has the power on button and the LEDs).
So he pulled out the "side board" from his laptop (Identical to my laptop) and installed it into my laptop, it worked, my laptop turned on, but it was in this "BIOS flash mode".
As we detected the problem, he pulled out his "side board" to place it back into his laptop, he didn't had any other working "side board". So I had to buy it from the "tech guy".
2 days ago, I took my laptop to the tech guy's place to continue shopping. I bought from him the speakers, the hard drive plug and the "side board". He said: "Ok, go get me the money while I install these things on your laptop."
I went to get the money and returned to pick up my laptop and go home.
When I arrived to my home, I plugged in the charger and pressed the power button and nothing happens, no LED, nothing. (I know the charger works).
I inmediately took my laptop back to the tech guy's place, told him the WHOLE story, and now he says "You deleted the BIOS when you powered on the laptop without the small battery, you must buy a small battery and install it, that is why the laptop won't power on".
He was about to close the shop (Friday), so I returned to my home, and on the way home I bought a small battery, then installed it on my laptop, and got the same result.
I think what he said is a total bullsh*t because there is only one way to get the "BIOS flash mode", the only way to get to that mode needs a FAT32 flash drive with the BIOS files, the charger and a USB keyboard. Then the user needs to plug in the keyboard and the flash drive, press Fn + R, plug in the charger and hold the power button for 5 seconds.
Also, the user can NOT delete the BIOS because it is read-only.
I think there is NO WAY to do that accidentally. I think he is playing dirty tricks to not replace the sh*tty hardware he sold me.
I'm planning to go there tomorrow on the morning (Monday) to fix that, but I want to be 100% sure that the "BIOS flash mode" situation was NOT something I caused. And I want to be sure to say: "You fool, the small battery is NOT a critical boot component".