Android Engineering Mode Is there a way to change between User and Eng mode on android devices? More specificity the Motorola Defy (2.2.2) and the Acer Iconia A500 (4.0.3) I need access to tools like dev tools. I dont mind if I have to root the DEFY.
No you cannot, that is done at build/compile of the source of the said Android version whatever that may be.

When the source gets compiled via 

. build/envsetup.sh


This is setting up the environment, and that reads in the potential devices via BoardConfig.mk within each device/product directory.

Its when lunch gets executed, the menu shows like this

$ lunch

You're building on Linux

Lunch menu... pick a combo:
     1. full-eng
     2. full_x86-eng
     3. simulator
     4. zte_blade-eng
     5. zte_blade-userdebug

Which would you like? [full-eng]


The above is the example of building the ROM for the Zte Blade, notice how userdebug and eng is prefixed!