Resurrecting a Pixel C

I'm putting off the post I need to write so I'm going to ramble a bit about resurrecting an old Pixel C tablet by sideloading a custom operating system. This is something that sounds scary but really isn't, so I thought I'd share in case anyone else has hardware in the cupboard and no desire to buy new, expensive kit.

Setting the scene

My tablet usage is pretty modest. For anything significant, I'll use a laptop / desktop or my mobile phone. My tablet is mostly used for video streaming (YouTube, Netflix, etc) and a bit of web browsing when it's the closest thing to hand. I am not a power user.

Many years ago (2016), I bought a Google Pixel C tablet. This was originally released in 2015 and was Google's first tablet under the Pixel brand. Other than having a name that is really annoying to search for, it was a fabulous piece of kit - feeling very solid and chunky. However for boring reasons, when COVID hit I moved and my Pixel C fell out of use.

Fast forward many years, and my iPad battery is dying so I thought I'd see about resurrecting the Pixel. Firstly, I hadn't realised how long it had been since it was last used - like a lot of people I know, my sense of time has been utterly smashed by two years of lockdown - so it was a bit of a surprise to discover Google stopped supporting it nearly six years ago (end of 2018). Consequently, although it fired up fine, it was hideously out of date with no path to catching up. It seems older versions of Android (8 in this case) have a problem connecting to modern 5ghz wifi connections and so my lovely hardware was dead unless I wanted to run a lower speed wifi network.

Why take the easy solution, eh?

So, with my brain telling me "this is only a few years old" (it's nine years old?!) I thought I'd look at bringing it back to life via the medium of a custom ROM. For the uninitiated, this is basically installing a new operating system package - pre-built with proper drives and so on - however is more complicated because tablets and phones tend to lock all this down to stop people fiddling and bricking the device. However, I'm (apparently) a grown adult so I'll fiddle if I damn well please. Plus, it doesn't work now so it's not going to get any less functional - perfect for some learning.

Get on with it

The hard part was really all the prep. I needed to find a good ROM, which I did via the application of Google and reading. LineageOS is a the gold standard for community-run operating systems, but even they have dropped support for the Pixel C. However there are some intrepid folk out there who are keeping the dream alive on the XDA forums and a helpful dev going by npjohnson is pushing out builds for the Sphynx project, via his forum thread. Sphynx is an unofficial build of LineageOS tailored for the Pixel C - perfect for me.

The instructions are good - I read them a few times before giving this a go because I was scared - and basically there are four stages:

1. Download adb and fastboot to your computer - this laptop is Ubuntu Linux so that was as simple as sudo apt install adb fastboot but Windows options are also available
2. Learn how to boot your tablet into the recover mode menu (for the Pixel C, with the device off hold Power and Volume Down)
3. Download the desired image - I just took the latest (lineage-21.0-20241019-UNOFFICIAL-sphynx.zip at the time) and it worked fine
4. Follow the instructions very closely

Extremely minor gotcha - I extracted the downloaded zip file to get a recovery.img file for page 3, then used the original zip for sideloading in step 4. Other than a couple of slightly alarming beeping sounds from the device, this was the only time I really needed to think once I got going. The whole process took about an hour, going very slowly and carefully, then additional time to set up the tablet (obviously it is wiped so you'll lose anything on it from before).

Behold

And it's working! There are some known issues - the camera doesn't work properly, apparently bluetooth is a mixed bag and the rotational sensors also don't work - but these haven't impacted my needs. If you like running your tablet in portrait mode, apparently this can be a pain. However, for me I have a shiny refurbed tablet that plays videos and doesn't keep turning off mid-video. Hurrah!

Overall, this is scary. But it turns out it is also easy. Hopefully others will give it a go and bring their devices back to life.

Sending email - redux

It feels like forever since I wrote my last blog post on sending email via a vanity domain but has actually only been a year. In that post, I noted that sending via SendGrid was optional and it should all be doable using Google servers. The SendGrid config has been mostly ok, but hasn't been perfect and I wanted to remove this free third party from my email tool chain so I've revisited the setup and got it working through the Google mail server.

Will this work long term? Hopefully, but I'm not convinced for reasons I've laid out below. Let's do this.

Sending email

First I needed an app password for your Google account, which is a bit of a buried in the security interfaces. You can find the admin console for app passwords here.

This is also reachable by going to Google account settings, under "How you sign in to Google" select "2-Step Verification" and the option for App Passwords is at the bottom of the page.

Next, to configure gmail to send via the Google mail server, I needed to set the outgoing mail, found in:

Settings -> See all settings -> Accounts and import -> Send mail as

Then adding / editing my intended outgoing email address with these details on the second page ("Send emails through your SMTP server"):

SMTP server: smtp.gmail.com
Port: 465
Username: Your google account (blah@gmail.com)
Password: Your app password from earlier
Secured connection using SSL ticked

Email security

This is a minefield and something I'm going to have to monitor to see how horribly I have broken things. First, this tool from Red Sift is great for analysing email security settings.

Deep breath...

SPF

To the DNS record, add:

include:_spf.google.com

and remove references to sendgrid to avoid too many lookups - this flags it as insecure.

DKIM

Without a full Google Workplace account, I can't upload a private key to Gmail so DKIM isn't going to work. Hopefully SPF will be enough. We'll see...

I think this also scuppers MTA-STS, but happy to be corrected.

DMARC

This is tricky. DMARC requires one of DKIM or SPF to pass tests properly in order to pass, then it suggest the receiving server takes a specified action (via the p flag). In this case, my DKIM check is going to fail so that is out. The SPF check passes the initial test however there is a further check to make sure the Sender and From headers are the same. In my case they are not, since Sender is gmail and From is my domain so check fails with a no-alignment error - thus the DMARC check itself fails.

I've "solved" this by setting the p flag in my DMARC DNS entry to "none" which just tells the receiving email server to deliver it anyway. It seems to work for my very limited testing sample, but obviously I'm not happy about this approach.

What is next?

I hope the SPF config will be enough to make my email work happily again, however I'm clearly hitting the limits of the free options in Gmail. If this doesn't work well enough, I think I'll move away from free options and look at something like AmazonSES which (from a quick read) will let me configure everything I need and charge me $0.10 per 1000 outgoing emails. This is probably the ultimate "correct" solution (unless I want to pay for a Google Workspace account) but is a lot more work and right now I don't wanna.