Motorola Droid 4

Tony Lindgren is currently working on mainline kernel support for the Motrola Droid 4 (Wikipedia, GSMArena, iFixit Teardown). He documented his work to get serial over USB on the following page:

I just got myself a used one via Ebay, since it’s a decent upgrade from the Nokia N9xx phones. It’s also quite cheap (30$ in US, 50€ after import to DE (shipping + customs)). Last but not least there is no newer phone available, which has a proper hardware keyboard.

CPU2x ARM Cortex-A9 @ 1.2 GHz
GPUPowerVR SGX540 @ 304 MHz
Memory1024 MB LPDDR2
Disk16GB internal, µSDHC Slot
Modem 1Quad-Band GSM/UMTS
Modem 2LTE (700MHz, mostly useless in EU)

The kernel used by Android is available on sourceforge. It is used together with a custom (non-standard) DT blob. Both sources combined give some information about the HW chips being used inside of the phone. I compiled a status table below:

FunctionChipmainline driver
Keyboard and Display BacklightLM3532patch
Temperature SensorTMP105no
ProximityISL29030only isl29035
PMICCPCAP 6556002yes
-battery monitoring-no
-RGB led-no
-capslock status led-no
-android buttons led-no
-Bluetooth-yes, WIP
Vibrator (via PWM)-no
Keypad (via SoC)-patch
UMTS Modem (via USB & SPI?)MDM6600no
LTE Modem (via USB)W3GLTEno
Primary CameraOmnivision OV2B3BA (OV8830)no
Secondary Camera?no

The bootloader is unfortunately locked down, but Cyanogen people got kexec working. So Android can be used as giant bootloader to load the mainline kernel via kexec. Details about that can also be found on Tony’s Droid4 page.