MacBook Air code PFM006 / PPN001 CPU capped @500mhz
Story: I decide to turn my family's Macbook Air 2017 into a backup machine. It was running slow, so Window was put on it at the repair shop before this by another person.
I install Debian on it but it can't play YouTube videos without lag...I was a little confused, decided to get a lighter distro.
I install MX Linux, the same thing happened. I thought it was the AV1 codecs, and after deactivating them on every browser, videos were playing better, so I thought that was the fix; it was NOT.
The laptop is still like a potato; loading takes too long, and I remember some user said it should play 4k video just fine.
so I ran the Apple Diagnostic tool; error codes show:
PFM006 /PPN001
Research result: possible defective motherboard, damaged SMC module, damaged battery temperature sensor. The CPU is capped at a max of 500 MHz...!!
No freaking wonder my old ThinkPad X200 seems to be faster.
So I open the back cover to check if anything is damaged. OH MY!! There was an ant colony in there.
After cleaning up the inside, I try resetting the SMC / NVRAM / PRAM a few times, but nothing changes.
While fixing the laptop and babysitting, I close the screen to go watch the baby. Come back and see the CPU frequencies work normally! I rebooted the laptop to see if it was permanent; it wasn't.
I had TLP installed and was playing with mbpfan.config settings... but nothing worked.
On idle the CPU frequencies seem to be normal, it's only capped when it's active.
I decide to do a sensor-detect check, remove TLP, and install the power-profiles-daemon instead.
BEHOLD! IT'S WORKING!
The CPU is at full speed now; browsing the web is speedy and instant.
I still don't know what fixed it. Maybe it was the closing and opening of the screen.
HTOP should have show the frequencies and temperatures by default, it would have saved me from distro hopping.