Galaxy S6 Reversed Touchscreen – Fixed

bɘxiᖷ – nɘɘɿɔƨʜɔuoT bɘƨɿɘvɘЯ 6Ƨ yxɒlɒᎮ

So I had this Galaxy S6 SM-G920I – not an Edge, the Flat model – that I’d restored, new front & rear glass, having been the endpoint of seemingly considerable energy transfer in the process known as “hissy-fit.” Anyway, it’s a fairly simple process to fit these quite decent Samsung handsets with new clothes, & I hate seeing good electronics go to waste (read – I smelt a profit so I did the work.)

When finished, it looked just like a new one – as pictured above. Except blue, not black. Which I personally think is the premium colour choice in Galaxy S6’s. Anyway, back to the story.

So I set the S6 up with a nice clean custom ROM from XDA, form & function combined – and none of that Samsung Touchwizz bloatware, logged in to the phone & ran it as a not-phone for a few days – to test that everything was good to go.

And it was good to go too, this SM-G920I was a sweet little Samsung. Next step – find a new home for it.

Which, when you’ve got a phone that’s only 1 generation old with a new exterior & a sleek, modernised Android implementation, is not an arduous task. Popular items mean prolific buyer numbers.

I bumped into the eventual buyer while I was out & about, we would have done the deal there & then except I had the security locked down with Google & Samsung & ESET accounts protecting the device from reactivation plus the storage space was encrypted too.

(Just because it wasn’t going to be my long-term daily driver, does not mean in any way that there is any excuse for lax security. Lock your devices down, what you write down innocently could easily be misinterpreted as guilty conversation.)

Without an installed SIM card or WiFi access, I couldn’t properly wipe my accounts from the phone, so I made an arrangement to see the buyer again in 2 days time. I was thinking I’d nip home, clear it as you usually do & that would be that. Err, no. The story really starts here.

I cleared my accounts alright, no problem there. Then booted back into the TWRP recovery to wipe the Data & Cache partitions before a final reboot to set it up for the client. Except it wouldn’t set up…

Nope. If I pushed the hardware buttons it’d do the right thing, but any touchscreen action was either ignored or gave an incorrect result. WTF?

To make matters worse, as it wasn’t our first transaction, the buyer had paid for their new phone up front. I’ve never come across this touchscreen misbehaviour before –  why now? Why me?

The first input screen after you’ve reset an Android phone is the WiFi connection screen. Selecting the local network was not your normal event but it got there easily enough – no alarm bells ringing anyway.

Entering the WiFi password, however, proved impossible (but did provide the clue for eventual discovery). The household WiFi has a password that begins with A – or a to be exact, but whenever I pressed the A key, I got an L. Eh? So the first real chunk of connectivity wasn’t happening, grrrr.

.oƚ bɘbɘɘn I ƨyɘʞ ɘʜƚ ɿɘƚnɘ ƚ’nbluoɔ I ɘƨuɒɔɘd ɘƨɿow nɘvɘ ƚud ƚxɘƚ ʇʇo-woʜƨ ʇo ʞnuʜɔ ƨiʜƚ ɘʞil ƚoИ .ƚuoyɒl bɿɒodyɘʞ ɘʜƚ oƚ ǫnibɿoɔɔɒ bɘƨɿɘvɘɿ ƨɒw ɘbɒm I yɿƚnɘ bɿɒodyɘʞ yɿɘvƎ

I tried reinstalling Samsung’s bloated Marshmallow OS, then the previous Lollipop version – same shit. I installed 5.1.1 & 6.0.1 as a giant .md5 images then tried 6.0.1 split into component chunks. Nah.

OK, let’s see if it’s the recovery image – TWRP, Philz & the factory recovery, rooted & original, all failed to fix the issue. I’m getting scratchy by now – I know the phone hasn’t had an impact to physically cause this issue, but I’ve replaced all the accessible software more than once & it’s still there…

So I tried again (& again & again) to figure a way through. It was then that I noticed that the A key is mirror-opposite to the L key – the L showed whenever I hit A. So I tried the S key – & got K. 0 gave 1 & 6 returned 5. Mirror imaging.

So now I knew how to describe the problem – reversed Y axis in the phone’s BIOS settings. X axis was OK, but Y was reversed. How am I gonna fix that?

Samsung have had their secret factory engineers codes fairly well published on the web – they’re not really all that secret any more. The web is a bit like that, especially when Samsung is if not the highest represented brand of web-accessing devices, then certainly one of the highest. The info was bound to leak.

I googled Samsung Y axis touchscreen reset, found that the hidden adjustment setting was accessible through keypad *#2336# (reverse-entered as #*2114*)  where a quick visual would let me ID the errant setting – it’d be an unmatched pair of numbers. I tapped the reset on that pair & closed out of the engineers menu to a working phone \0/. Reboot wasn’t even required.

A poorly-timed lesson for me, I could have done without the stress of the impending product handover looming. But having learned something new & valuable, was definitely a good day after all.

In case you’re wondering, no, I didn’t share the troubleshooting antics I’d been through with the new owner. No need to bother them with unnecessary concerns. They know who to talk to should a problem arise.