Monthly Archives: October 2018

Android smartphone “Cubot Echo”

Smartphone

Cubot is a Chinese Android smartphone brand that offers a wide variety of inexpensive phone models. With the Cubot Echo (released in 2016) you get surprisingly good quality at a low price.

One of the main advantages of Cubot smartphones is their native Android version (stock Android). Many smartphone manufacturers heavily modify Android and add tons of “features” and apps that you don’t really need and are more annoying than helpful. They hope to create a unique customer experience that makes users get accustomed to their brand so they choose the same brand again for their next phone. Moreover these modifications often slow down overall performance and introduce security holes.

Cubot ships all their models with an almost native Android version. No modifications (except necessary adaptions to hardware), no annoying apps or background tasks that cannot be removed, etc.

Cubot Echo
https://www.cubot.net/smartphones/echo/spec.html

Pros
+ Very good overall hardware quality compared to cheap price (unbreakable display, strong body for outdoor use)
+ Good display, camera quality and performance compared to cheap price
+ Large 5.0 inch display
+ HDR photography
+ Up to 128 GB micro sdcard (supported, but not included)
+ Native Android user experience, no annoying modifications or add-ons
+ Removable battery
+ Cheap price

Cons
– Android security patch level only from 05.06.2017, but latest firmware update (which will be installed automatically after setup) DOES include security patch for WiFi WPA2 KRACK attack (build 08.02.2018). Android 6 Marshmallow does no longer receive security updates from Google, but you can install the unofficial Android alternative LineageOS based on Android 7 Nougat.
– No 4G / LTE support
– A bit heavy
– Released in 2016, a little bit outdated

Verdict
You can get the Cubot Echo for as cheap as 60 EUR. If you can live with the security issues and the missing LTE support, that’s a definitive buy. Especially considering that the upcoming Google Pixel 3 flagship for 850 EUR guarantees Android security updates for only 3 years. You could buy 14 Cubot Echos for that price. And the Google Pixel 3 does not have a removable battery, which makes it very hard to replace.

Cubot comparison chart

Cubot EchoCubot J5
Android VersionAndroid 6 Marshmallow
(no longer supported)
Unofficial support for LineageOS
based on Android 7 Nougat
Android 9
ProcessorMT6580 1.3 GHz Quad-coreMT6580 1.3 GHz Quad-core
Display5″ IPS
(1300:1 contrast)
5.5″ IPS
(18:9 format, 1300:1 contrast)
Brightness (cd/㎡)450450
Memory (RAM / ROM)2 GB / 16 GB2 GB / 16 GB
Max. Additional Storageup to 128 GB (not included)up to 128 GB (not included)
Camera (Back / Front)13 MP / 5 MP8 MP / 5 MP (interpolated)
LTEnono
Extras – Micro + standard dual SIM (no eSIM)
– A-GPS
– USB OTG
– Special sound chip with big speaker
– Unbreakable case
– Dual nano SIM (no eSIM)
– A-GPS
– Curved display sides
– Gradient color case
Battery3000 mAh (removable)2800 mAh (removable)
Price~ 60 €~ 65 €
Cubot NovaCubot Magic
Android VersionAndroid 8.1 OreoAndroid 7 Nougat
ProcessorMT6739 1.5 GHz Quad-coreMT6737 1.3 GHz Quad-core
Display5.5″ HD+
(18:9 format, 1300:1 contrast)
5″ IPS
(1300:1 contrast)
Brightness (cd/㎡)450450
Memory (RAM / ROM)3 GB / 16 GB3 GB / 16 GB
Max. Additional Storageup to 128 GB (not included)up to 128 GB (not included)
Camera (Back / Front)13 MP / 8 MP13 MP / 5 MP
(13 MP +2 MP Dual Back Camera)
LTEyesyes
Extras – Dual 4G nano SIM (no eSIM)
– A-GPS
– Fingerprint sensor
– Dual micro SIM and dual standby (no eSIM)
– A-GPS
– Curved display sides
Battery2800 mAh (removable)2600 mAh (removable)
Price~ 70 €~ 70 €

Add entropy to KVM virtual guests (Why is key creation so slow?)

Problem

Cryptographic key creation (GnuPG, SSH, etc.) in virtual guests may be very slow because there is not enough entropy.

$ cat /proc/sys/kernel/random/entropy_avail 
7

Solution

Add /dev/urandom from virtual host in virt-manager. Click on “Add Hardware”.

Add “RNG” device.

This is what will be added to the qemu xml file in /etc/libvirt/qemu:

<domain type='kvm'>
  ---
  <devices>
    ...
   <rng model='virtio'> 
     <backend model='random'>/dev/urandom</backend> 
     <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> 
   </rng> 
 </devices> 
</domain>

In the virtual guest, install “rng-tools” (Ubuntu 18.04).

$ sudo apt-get install rng-tools

If something goes wrong, the rngd daemon will complain in /var/log/syslog.

Oct 13 22:48:07 guest rngd: read error 
Oct 13 22:48:07 guest rngd: message repeated 99 times: [ read error] 
Oct 13 22:48:07 guest rngd: No entropy sources working, exiting rngd

If rngd is working correctly, check entropy level again.

$ cat /proc/sys/kernel/random/entropy_avail
3162