Recovering a Factory Reset Hudl 1

Background

I have a couple of Hudl 1 devices that used to be the kids'. I want to re-use them as control interfaces for some IoT stuff - but first they needed to work.

Batteries seem OKish and the devices booted, but they had lots of old cruft on them. My first mistake was to factory reset them - although they still started up fine they were now stuck in the initial setup wizard: they tried to connect to the internet, but appeared to fail to connect to some setup server and reported that they didn't have internet access (although they clearly did).

There is long history of Tesco’s ‘misdeeds’ re HUDL support, starting as early as January 2019. Tesco actually switched off server access without warning at that point, initiating a storm of protest which ended up in an adverse report in the press which forced them to think again and eventually restore access. We all thought they had learned their lesson, but no such luck. Correspondence this year (2020) has confirmed that they have no intention of providing any further support for the HUDL.

Hudl couldn't access internet dialog
Wireshark trace

Investigation

A lengthy web-search, followed by a quick investigation and a Wireshark capture of the traffic from the Hudl during boot reveals that the failure appears to be around the TLS set-up when connecting to https://device.mobile.tesco.com/. Pointing a web-browser at that site shows that its certificate expired on 26th June 2020. It turns out that if we can set the Hudl's date and time to a point before that date, we can fool it into thinking the server certificate is still valid. We can then make some progress.

My Hudls

My Hudls are the first generation Hudl devices, with these identifiers:

  • Model number: Hudl HT7S3

  • Android Version: 4.2.2

  • Kernel Version: 3.0.36+

  • Build number: JDQ39.20140424.153851

I have 3 of them, ad I had them all stuck in Setup. I've been working on a couple of options for bringing them back to life ...

Expired certificate details

Recovering and Fixing the Hudl - Option 1: No tools needed

This option needs nothing other than the Hudl and an internet connection. No ROOTing, no custom firmware, no debugging tools. Simply. follow the detailed instructions linked below and you'll be back in business in no time ...

A quick note on applicability: These instructions are aimed at the Hudl 1 running Android 4.2.2. I have had reports that steps very similar to this method can be also be performed on a Hudl 2 to recover it from the same fate, but I don't have a Hudl 2 device to test and so can't document any differences based on my own experiences. Note that this problem is reported to only affect Hudls running Android 4.2.2; HUdl 2 devices that were upgraded to Android 5.0 are not affected.

There are some downsides to this method, which are described in the bullets below. Most of the issues are permanently solved by option 2, but for many people this procedure will be enough to get them running again:

  • This work-around will have to be repeated if you factory re-set your device again.

  • The method will only work while the Tesco server is still available on the internet - we have no idea if or when Tesco may de-commission it. Tesco have said that they no longer support Hudl 1 or Hudl 2 devices, and we believe that it is only a matter of time before the URL(s) go dead.

  • As time passes it is possible that this work around may stop working for other reasons.

Recovering and Fixing the Hudl - Option 2: Flashing a Custom Firmware

I've created a custom ROM that you can flash onto your Hudl 1 device. This will fix the problem permanently and allow you to factory reset your device as much as you want without issues. There are detailed instructions for downloading and flashing the custom image, as well as links to the code I have used so that you can investigate how the changes were made (and make some of your own if you want).