Manta MID721QC

Very cheap 7" tablet distributed probably under dozen different brands:

• Allwinner A33, quad-core A7 running at 1.2GHz with Mali400 graphics
• 7" 800x480 display with poor viewing angles (I can say that just viewing it in vertical position can give strange impression as left and right eye see slightly different images) and capacitive multitouch
• WiFi
• VGA front camera
• accelerometer
• Android 4.4.2
• 512 MB RAM, 4 GB Flash
• microphone and (poor) speaker
• micro SD slot
• roughly 4 hours on battery (WiFi, internet), up to 6 hours (WiFi disabled, minimum brightness, PDF reader)

 I believe this tablet had factory installed trojan - at least I don't think I could infect it just in an hour and such "accidents" are not rare. This must have pretty fresh mutations as VirusTotal says that file was first scanned on 2015-12-12 (https://www.virustotal.com/en/file/401a320b23213932b222cc0afb8c69acb12efb9cbeb1884f0873a581d0192f96/analysis/)
Trojan was embedded in GoogleQuickSearchBox.apk (system application) and required rooting to remove. I believe it was responsible for opening fishy "antivirus" site once or twice and it also tried to install "WiFi Booster" (another malware?).
Case is easy to open with bare hands.
PCB markings: AL-Ax3-Q8-V1.1 2015-01-21

Serial number from sticker vanished just after few hours of light use; nice trick to void varranty

2200mAh cell (still lot of spare space), main board

357090 (3.5mm x 70mm x 90mm) 2200mAh protected cell. It looks like 3575100 (3000-3500mAh) should fit also.

unpopulated: vibration motor?

ESP8089 WiFi (close cousin of ESP8266); FBNL83A51K3BAAWP 32Gb NAND from Spectek

2x K4B2G0846 2Gb DDR3

LPA4890CM audio amplifier; up to 350 mW output power in this configuration, in reality probably 50 mW, might be worth tweaking

'7660 voltage converter (backlight power supply?)

AXP223 power manager

miniature camera (VGA)

8 ohm speaker with no markings

It looks like this tablet has now included in Linux mainline: http://linux-sunxi.org/AL-AX3-Q8