SPI Keyboard/Trackpad on MacBookPro12,1 Not Working after 10.11.3

reminds me of the problem I had with my previous MBP non-retina 13...the HDD ribbon cable was replaced 5 times in the span of 2 years. a $20 part taking it down over and over. That's what made me upgrade to a retina MBP 13 last year, but then a this kybd/TP stop working problem decided to crop up. 1st time Apple took a month of playing around (Nov 2015) until they decided to replace the kybd/TP, only for the problem to sprout up again May of this year briefly, only to completely fail in July, after the warranty had already expired (isn't that the luck!).

I thought I saw somewhere online that someone had this problem with the keyboard and trackpad failing, just stopping out of the blue, etc...and they opened their system up, put a napkin under a cable for the keyboard/TP and it fixed it. If thats the case, then Apple is relying upon sub-part cables for their systems that we pay thousands of $$'s for. Thankfully I have an external monitor, kybd and mouse I can use until whenever Apple gets around to fixing this problem, as long as I keep being content with having to use my $1600 laptop as a desktop....my luck they'll finally get around to fixing it after I give up and go back to a Windows system cause I want the mobility again

I am having the same issue. The apple store tried to replace some cables, which works for a while but now the issue comes again. My keyboard and trackpad usually stops working at the same time (seems randomly). I tried a clean reinstallation (el capitan) but doesn't solve the problem. Has anyone tried to downgrade to Yosemite?

I went to genius bar the second time last week due to this issue, got the cable fixed. However, yesterday, keyboard and trackpad started stopping working again. Really hopeless about replacing the cables again and again. I need some way to solve it since I'm tired of going to apple store every couple of weeks and wasting my paid working days.

Same thing. I sent the laptop to the store for a warranty repair. They replaced some cables and said the issue is fixed.

Just two days and the issue came back again.

This *****

Yes, I am having the same issue.

Both trackpad and keyboard sporadically fail on boot. The only thing that helps is repeated reboots until I get lucky and can login. The issue exclusively occurs upon booting for me and doesn't randomly start during operation.

Every time the culprit seems to be HSSPI, the logs are full of error messages.

My guess is that the driver for the keyboard/trackpad combo has one retransmission error threshold for initialization of the device and another for regular operation(higher than the former). The HSSPI cable may be flawed, causing a higher number of transmission errors with increasing age of the mac. The two different thresholds could be an explanation for why problem usually appears first on boot.

See also Force Touch trackpad stopped working . The issue is not exactly the same but the culprit there also seems to be the HSSPI and a cable replacement seems to be a fix (at least until the cable fails again)