Cubot Rainbow

A short review of another smartphone. I’d like to say it’s another small one, but in my opinion, 5 inches still doesn’t qualify as “small”—though who knows what tomorrow will bring.
As always: inspection, teardown, tests, and conclusions.

What can I say? The Cubot Rainbow is another representative of the “building block” series based on the well-known MTK6580 system-on-chip (SoC). The Chinese engineers have essentially created another configuration option. Whether anyone will like it, I don’t know, but I’ll try to give you a detailed account of it.

First, the specifications.
Colors: black, white, gold, red
Processor — MTK6580, 4 cores
GPU — Mali-400 MP
Operating system — Android 6.0
Memory — 1 GB RAM, 16 GB flash storage.
Display — 5 inches, 1280x720 resolution
Network type GSM: 2G: GSM 850/900/1800/1900 MHz
WCDMA: 850/1900/2100 MHz
Wireless interfaces — Wi-Fi: 802.11b/g/n, Bluetooth 4.0
GPS
Memory card slot — MicroSD, supports up to 32 GB.
Audio output/microphone — 3.5 mm jack.
SIM card type — 2 micro-SIM cards
Front camera: 2 MP
Main camera: 8 MP
Battery: 2200 mAh
Dimensions: 142x72x8.8 mm

From the specifications above, the only difference seems to be the amount of flash storage; nothing else, as far as I can tell. In other words, they basically took the same Ulefone U007, added flash storage, put it in a different case, and got a new phone. But there are actually more differences, and I’ll try to find out what the specs don’t tell us.

The phone arrived in a small black box that had suffered a little during shipping.


The box also lists a few basic specifications.


The packaging is a little unusual: the inside also includes instructions for getting started with the phone. It reminded me somewhat of the packaging for Schneider installation products.
The package includes:
1. Smartphone
2. Charger
3. USB-to-MicroUSB cable
4. Case
5. User manual


A manual is included, with information in Russian—aimed, let’s say, at complete beginners.


The cable and charger are completely standard, nothing unusual—not even the white color. The charger is sealed, but I doubt there’s anything remarkable inside; it’s most likely an ordinary, inexpensive unit of the kind bundled with the vast majority of phones.


My first impression of the phone was mixed. On the one hand, it’s a fairly neat-looking device; on the other, the case is rather bulky.


The phone is comfortable to hold in this case, but there are a few downsides: it makes the phone noticeably bigger, the side buttons are harder to press, and it looks bulkier.
The photo shows it next to its “classmate,” the Doogee X5 max.


The case has a rather odd shape; it sort of lifts the phone off the table. To be honest, I liked the case in the previous review much more—it was at least softer. On the other hand, this one is just a bonus.




At first, you might think the back of the case is perforated. It isn’t; those are just little bumps, facing inward. I think there’s a chance they’ll gradually scratch the paint on the back cover.


Take the case off and everything “goes back to normal”: the phone returns to its regular dimensions and becomes a little smaller than the Doogee X5 max.


The phone arrived in “gold.” I was worried it would look like “a magpie’s delight,” but in reality it looks quite good; the color isn’t too pronounced.


On the right side are the usual three controls: the power button and volume buttons.
There’s a raised rim around the edge to protect the glass from scratches when the phone is placed face down. In the photo, the rim looks white all the way around, but don’t worry—it’s actually the same color as the front panel.


At the top is a MicroUSB port for charging and connecting to a computer. OTG is also supported. Next to it is a 3.5 mm jack for headphones or a headset.
I’d like to share one observation. It’s good—actually, great—that manufacturers have finally settled on a single standard for connecting a charger. (Remember all the different connectors we used to have?)
But there’s one small thing. I’m fine with the port being on the top or bottom, at the edge or in the center, but why don’t they orient it the same way on every phone? I know it’s just a matter of habit, but on one phone the plug goes in one way, while on another you have to turn it 180 degrees. Reversible USB cables have appeared now, so they could include one in the box.


At the top of the phone are the earpiece, a 2 MP front camera, and the proximity sensor. I’d try hiding the proximity sensor; it would look a little neater.


The back cover has a textured finish, so the phone doesn’t slip in your hand.


At the top of the back is the 8 MP rear camera and an LED that serves as both a flash and a flashlight. The camera protrudes noticeably above the back cover. I don’t think that’s a great design choice; it could have been recessed so it sat flush with the cover.
There are openings for the second speaker at the bottom.


Here’s how it looks next to the Doogee X5 max. In this case, I personally prefer the phone under review, but that’s a matter of taste and habit. This phone has more of a “feminine” design, while the Doogee X5 max is better suited to men.


Compared with the Ulefone U007, this phone is noticeably heavier: 165 grams versus 135. With a case, it can rival the Doogee X5 max in weight (188 grams). But the Doogee X5 max has a higher-capacity battery, so I’m not sure where all this weight comes from. I suspect it’s due to the battery’s extra casing, a heavier frame, and a larger internal plastic cover over the electronics.
Even so, the phone doesn’t feel heavy in your hand, probably because of its shape. For example, the Doogee X5 max feels bulkier.


As I mentioned above, the top of the phone’s front panel houses the camera, earpiece, and proximity sensor. There’s also a power indicator at the top. It glows red while charging and green when fully charged (or, more precisely, above 95%). When the charger is disconnected, the indicator stays off, but it starts flashing red when the battery is low. It isn’t very bright, so it definitely won’t be visible in direct sunlight.


Let’s remove the back cover. The first thing you notice is that it’s painted only on the surface, rather than being colored throughout, which would have been much better. That said, I don’t know whether this color can be molded into the plastic, or if that’s only possible with solid colors.
This kind of paint can wear off, although it feels reasonably well done. Still, there’s a chance it will.


The battery is removable. There’s a protective sticker on the contacts, which I had to remove this time to get the phone working.


At the top are a memory card slot and two micro SIM slots. You can’t replace the cards without removing the battery.


At the bottom are the speaker and GSM antenna. It’s interesting that the GSM antenna is placed at the bottom rather than the top.


The battery sits quite firmly in its “tray”; nothing rattles or falls out.


Installing the cards is no problem, but removing them takes some effort, especially the memory card, which is difficult to pull out.


Since I’ve already taken off the back cover and removed the battery, I might as well take it apart further.

Before moving on to the software tests, I'll say a few words about the phone's screen. To me, it looks no different from the previous models; I think it uses the same or a very similar panel. There's also a slight black-level glow, but the screen is bright. Still, with this wallpaper it looks more washed out than the previous models.


That's it for the exterior and interior; let's move on to the software.
There aren't many apps included. One plus is the convenient app menu, which shows the most frequently used apps at the top. One downside is that there's no gallery app for viewing photos.


A brief overview of the phone's specs. It currently has the latest firmware version installed.
Less than 100 MB of the 11 GB of flash storage available to the user is occupied, so there's plenty of room to work with.


As always, the first thing I checked was the Wi-Fi module's performance.
In my standard test, which checks the connection at a long distance from the router, the phone connected without any problems, but when I tested the speed, a connection lost message appeared.


The standard test around the apartment.
1. About 12 m away, with reinforced-concrete walls in between and no direct line of sight. The corridor helps the reflected signal travel better.
2. About 6–7 m away, with several reinforced-concrete walls. The signal was much better in this test than in the previous one, even though the reception conditions were only slightly better.
3. The room next to the one with the router.
4. 1.5 m from the router.


Sensors are another important part of the phone. There aren't many of them, but at least there are no fake sensors: everything shown as active in the overview screenshot is actually present.




General information from CPU-Z. One useful but also disappointing detail is that there's no root access. Most people don't need it, of course, but if you do, you may run into problems.


More detailed information from Aida64. There are a lot of screenshots, so I've hidden them behind a spoiler, especially since the information is quite specialized and rarely needed by ordinary users.

The familiar AnTuTu version 5 test.


And of course, the same test, but version 6.


And then there are the well-known 3DMark and PCMark tests. Interestingly, the software has only one rating for this phone from other users.


Testing the speed of the RAM, as well as the external and internal flash memory.
The test used an unbranded 32 GB microSD card.


Epic Citadel served as the gaming test. The app ran without any problems at both the standard quality settings and Ultra mode; there were no freezes or unexpected shutdowns.


The AnTuTu Video test, however, disappointed me a little. It wasn't so much the test itself as the fact that my Full HD test file, which I use to check all devices, didn't play very smoothly.


On the plus side, this phone has another significant difference from the previous Ulefone U007: its touchscreen recognizes 5 touches, not 2.


I showed the battery test above, but the runtime test is more interesting. The test was run at 75% brightness, playing a Full HD file with a 10 Mbps bitrate.
The test video played for about four hours and twenty minutes, a little longer than on the Ulefone with the same battery and processor, but shorter than on the Doogee by roughly the difference in their battery capacities.

I also want to mention a curious behavior of this device that I still haven't been able to figure out. Almost every time I connect the charger, the charge percentage drops, and only starts rising after 5–10 minutes. And according to the monitoring data, the voltage drops too, not just the percentage. This is a first for me; it gives the impression that the phone discharges the battery a little before it starts charging it.


I tried testing it in the YouTube app, but it was very inconvenient, so I eventually had to give up.


I have no particular complaints about the GPS module; its performance is roughly on par with the Doogee X5 Max. In plain English, it's average.


Finally, let's look at the quality of the built-in camera. I tested the rear camera, since it's the one most often used for taking photos.
I compared it with the Vernee Thor smartphone. Of course, I could have compared it with a camera, but I thought it made more sense to compare similar devices.
The review uses compressed images (I couldn't upload the originals); the full-size versions are available here — download.
From what I can tell, the images have a slight green tint, but are sharper than those from the Vernee Thor. You can correct the tint in Photoshop, but you can't improve sharpness, so I think the camera performs better here.







And so the photos wouldn't all be taken in bright sunlight, I took a couple more at sunset.





Now let's list the pros and cons of this phone.
Pros
Although appearance is subjective, in my opinion the phone looks fine.
Neat assembly, with no play or creaking during use
Stable software performance
The battery capacity matches the stated specifications.
OTG support and a battery charging indicator.
Case included.
A reasonably good camera.

Cons
2200 mAh battery
The case isn't very convenient
The WiFi module's sensitivity is not very high.
The charging controller's operating algorithm is unclear.
It's hard to say how durable the back cover's finish will be.

My take: this is yet another “kit” phone, assembled from another combination of components. Compared with the Doogee X5 max, it has a smaller battery and no fingerprint scanner, but more flash storage and OTG. Compared with the Ulefone U007, it also has more flash storage, a five-point touchscreen and OTG, but the battery is the same size and it weighs more.
Judging by the amount of RAM and the processor model, this is another basic phone that can also handle less demanding tasks and web browsing; it has enough resources for that. But if you want to play games, you'll run into the battery's rather low capacity again. For everyday tasks (calls, a little reading, browsing the internet, listening to music), the battery will last a day (at least until evening); for more demanding use, probably not.
I liked how stable the software is, although the unusual battery charging process is puzzling. The phone's configuration is also better balanced.
I've been using the phone for more than two weeks and haven't noticed any other problems.

I hope this review is useful and helps you choose a smartphone.

With the Rainb coupon, the price is $63.99. The coupon has been tested.

The product was provided by the store for review.