Monthly Archives: October 2018

Android smartphone "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, 16 GB ROM
+ Plain 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

Verdict
You can get this Android smartphone 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 EchoCubot J3
Android VersionAndroid 6 Marshmallow
(no longer supported)
Unofficial support for LineageOS
based on Android 7 Nougat
Android 8 Oreo Go
ProcessorMT6580 1.3 GHz Quad-coreMT6580 1.3 GHz Quad-core
Display5" IPS
(1300:1 contrast)
5" TN
(18:9 format, 1000:1 contrast)
Brightness (cd/㎡)450450
Memory (RAM / ROM)2 GB / 16 GB1 GB / 16 GB
Max. Additional Storageup to 128 GB (not included)up to 64 GB (not included)
Camera (Back / Front)13 MP / 5 MP8 MP / 5 MP (interpolated)
LTEnono
ExtrasMicro + Standard Dual SIM, A-GPS, USB OTG, Special Sound Chip with Big SpeakerDual Nano SIM, Face ID, A-GPS,
Energy efficient
Battery3000 mAh (removable)2000 mAh (removable)
Price60 €50 €

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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
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