UMI Zero full review

We've all heard of Samsung, Sony, HTC, Motorola and LG. UMI? Nope. But this Chinese smartphone manufacturer sells the octa-core Zero, the world's thinnest dual-SIM phone that has some flagship specs and right now is available for a tiny $203 (around £134). Even when it's not on offer it costs less than £300. Is it a steal? Read our UMI Zero smartphone review to find out. Also see: Best smartphones and Best Android phones.

UMI Zero smartphone review: Price and UK availability

UMI's Zero isn't officially available in the UK, but our sample was sent to us by, which is happy to ship to the UK. The only caveats to buying the UMI Zero from abroad is slightly longer delivery and that the supplied super-fast charger has a two-pin plug (we picked up an adaptor on Amazon for a quid). Read our advice on buying grey market tech here.

The usual selling price is $463, which works out around £295, but right now the UMI Zero is on sale at $203 - a staggeringly low £134. Note that you may incur extra charges from Customs, although we had no such problems. says it has plenty of stock available.

At £134 - or even at £295 - the UMI Zero is priced well below the flagship phones with which its spec competes. Also see: Best budget smartphones.

UMI Zero smartphone review: Design and build

The UMI Zero is the world's thinnest dual-SIM smartphone, and at just 6.4mm it's slimmer than even the 6.9mm iPhone 6. Its front and rear glass panels, minimal screen bezels and tall 146mm body remind us of Sony's Xperia line-up, giving it a premium look that also feels good in the hand.

This phone is extremely durable, with its glassware protected with Corning Gorilla Glass 3, and the single-piece chassis crafted from aircraft-grade aluminium-magnesium alloy. Nevertheless, the UMI Zero is supplied with a Z-shaped case that clips on to the rear. It's flimsy but light, and slightly raised at the front to protect the screen when placed face down on a flat surface.

As with the majority of Android phones you get three touchscreen buttons below the screen, here for Options, Home and Back (long-pressing the Home button brings up the recent apps menu). Unusually the power button is found on the left side below the volume rocker, but it's ergonomically positioned for righthanded users. Meanwhile, on the right you'll find a SIM tray that will accept either two SIMs or one SIM and a microSD card. The 3.5mm headphone jack and Micro-USB charging port are also reversed, with the former at the bottom and latter at the top.

On the rear is a small speaker, while the 13Mp camera and dual-LED flash sit not in the middle but at the top-left corner - possibly a result of the Zero's ultra-slim design.

One issue for some users will be the lack of a notification LED when you receive new texts and emails, although since our review a firmware update has corrected this issue (see Software).

UMI Zero smartphone review: Screen

For the display UMI has taken one of Samsung's Super AMOLED panels. Super AMOLED is just like standard AMOLED, but thinner and more energy-efficient. AMOLED doesn't require a backlight and produces very good contrast, but can display oversaturated colours - fortunately, though, we quite like this vibrance.

The display is 5in with a full-HD resolution of 1920x1080 pixels, equating to a very high pixel density of 441ppi. Text is sharp, images are clear and video looks great.

UMI Zero octa-core dual-sim smartphone review

UMI Zero smartphone review: Hardware and performance

UMI's Zero is an octa-core smartphone, running the 2GHz MediaTek MTK6592 Turbo processor with ARM Mali-450MP4 graphics and 2GB of RAM. In comparison to Samsung's Exynos 5410, which combines four ARM Cortex A-15s and four A7s and can only ever run four of its eight cores at once, this MediaTek chip has eight Cortex A8s that can all run simultanously.

Its significantly stronger multi-core over single-core performance in Geekbench 3 came as no surprise then, with the UMI turning in 2489- and 445 points respectively. That's a good performance, up there with the Qualcomm Snapdragon 800 and nVidia Tegra 4 quad-core chips of this world and phones such as the LG G3 (also see: What's the fastest smartphone 2014/2015).

We also ran the UMI Zero through SunSpider and GFXBench 3.0, in which is recorded 1090ms and 13fps (T-Rex) respectively. The JavaScript score isn't bad, but the Mali-450MP4 graphics clearly aren't up there with those of the best Android flagships. UMI notes that the MTK6592 Turbo abandons Imagination PowerVR SGX. Nevertheless, we found the Zero fine for watching movies and playing games, although it could become very warm in use.

UMI Zero smartphone review: Storage, connectivity and extras

At this price point the UMI Zero's storage and connectivity specs are perfectly reasonable. You won't get the latest 802.11ac Wi-Fi (maxing out at the more standard 802.11n), NFC or 4G connectivity, but there is Bluetooth 4.0 and GPS. If you're buying a phone from abroad it's important to note the frequency bands on which it operates, and the UMI Zero runs on 2G and 3G bands GSM 850/900/1800/1900MHz and WCDMA 900/2100MHz.

Storage-wise there's 16GB built-in, and if you're not interested in the phone's dual-SIM functionality you can instead insert a microSD card up to 64GB in capacity. It's either/or, though, not both. Don't forget that this being an Android phone you can also take advantage of Google's own and third-party cloud-storage services.

UMI Zero smartphone review: Cameras

The UMI Zero is fitted with a 13Mp Sony IMX214 f/1.8 rear camera with a dual-LED flash and fast 0.3-second autofocus, plus an 8Mp front camera that's great for selfies and video chat.It supports several useful modes, including Multi angle view, Panorama, Face beauty, Burst, Live Photo, Gesture Shot and HDR (Gesture Shot and Face beauty also work with the front camera). Missing is the ability to add filters and effects, but these can be applied using third-party apps in any case.

Photos taken on the UMI Zero were of a decent quality, certainly not to be argued with at this price.

UMI Zero smartphone review: Software

Here's the one drawback for some users: the Umi Zero is sold rooted, and is preinstalled with SuperSu from Chainfire (an app that allows for advanced access management of any apps that require root). This may well appeal to tinkerers, but for other users it prevents OTA updates. The UMI Zero runs Android 4.4.2 KitKat, however, which is a fairly recent version of the OS.

Just after we published this review UMI contacted us to inform us a firmware update was available to download from its website. This update is said tobrings a few fixes and optimisations to the UMi Zero, including enhanced battery performance, new quick toggles, camera optimisations and the addition of notification lights.

It's a stock implementation of Android, and includes full access to Google Play. Unusually, apps such as YouTube and Play Music are not preinstalled - if you want them just download them free from Google Play.

One difference you will notice is the extra ads. While Android users will be familiar with ads popping up as they close third-party apps, they'll likely be surprised by the occasional ad popping up as they close Google apps such as Gmail or even the alarm clock.

There are a couple of extras with Smart screen and Air gesture, as seen on Samsung phones, although we didn't manage to get either to work during our testing.

UMI Zero smartphone review: Battery life

The UMI Zero is fitted with a high-capacity 2780mAh lithium-polymer battery, and supplied with a special charger (note the two-pin plug) that can charge the battery up to 51 percent in 14 minutes, or give you enough juice to talk for 2.5 hours in five minutes. We did find that the UMI became rather warm during charging, however.

In common with other flagship phones it has an Ultra power saving mode that switches off screen colours, background mobile data usage, Wi-Fi and Bluetooth and limits the number of apps you can use at any one time to prolong life. You can also schedule times for the phone to switch on and off each day, which will be useful if you want to use it as an alarm clock but not receive irritating middle-of-the-night calls or waste battery life.

With normal use UMI says you can expect 21 hours life, which means you'll need to charge it every night.

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UMI Zero: Specs

  • 5in full-HD (1920x1080, 441ppi) Samsung Super AMOLED display with Corning Gorilla Glass 3
  • Android 4.4.2 KitKat (rooted)
  • 2GHz MediaTek MTK6592 Turbo octa-core (8x Cortex A7) processor
  • 2GB RAM
  • 700MHz ARM Mali-450MP4 graphics
  • 16GB storage
  • dual-SIM or SIM plus microSD slot (up to 64GB)
  • GSM 850/900/1800/1900MHz, WCDMA 900/2100MHz
  • 802.11b/g/n Wi-Fi
  • Bluetooth 4.0
  • GPS
  • 13Mp rear camera, 0.3-second autofocus, f/1.8, dual-LED flash
  • 8Mp front-facing camera
  • 3.5mm headphone jack
  • supplied with Zero case
  • 2780mAh lithium-polymer battery with quick-charge technology (51% in 14 minutes, or 150 mins talktime on a 5-minute charge)
  • 70.5x6.4x146mm
  • 145g