COM0. In the default WinCE image (BSP) the COM0 is being used as debug port, however you can configure it as normal serial port.

To change the runtime OS feature you will need the WinCE Platform Builder 5.0 (for WinCE5.0)/Visual Studio 2005 for WinCE6.0, as well as the BSP (board support package) that we provided in the shipped DVD. For application development you can use the EVC (Embedded Visual C++). 
There are evaluation versions of the above mentioned tools available on the Microsoft download site, full version of those tools can be bought from a local Microsoft distributor.

Be sure to copy it to the folder "Resident Flash".

There are three ways to achieve this:
1, Add the application (MyApp.exe for example) and its shortcut to the NK, and add the shortcut to the StartUp folder;
2, add the application to the NK and add something like below the registry:

[HKEY_LOCAL_MACHINE\init]
"Launch80"="MyApp.exe"
"Depend80"=hex:1E,00

3, by modifying the registry we can even replace the shell (explorer.exe), for example:

[HKEY_LOCAL_MACHINE\init]
"Launch50"="explorer.exe"
"Depend50"=hex:14,00, 1e,00

replace the "Launch50"="explorer.exe" with "Launch50"="MyApp.exe" so that we can disable the explorer and set our own application as the default sheel.

MTD partition is defined in the file "arch/arm/plat-s3c/include/plat/partition.h", you may modify the partition information by modifying this file.

Normally such "bad blocks" are not real bad blocks. These blocks can be marked as bad blocks due to some faulty operations. Generally we can have this solved by running the "nand scrub" command in the uboot prompt, note that "nand scrub" will erase everything in your NAND, so please be sure to backup your data before doing this. Anyway, a few "real" bad blocks in the NAND Flash is normal and allowed and they would not effect anything.

There are two possibilities:
1. The kernel image (zImage) has not been well installed.
In this case you just need to follow the user manual to install the zImage.

2. Incorrect u-boot parameter.
Is it possible to move my application software into the on-board NAND flash instead of CF/SD? 

There is already a rootfs (rescue rootfs) in NAND flash for our every board. Surely you can use on board NAND flash, our boards leave a big part of Nand Flash for the user's application. The board user manual writes detailed steps for burning vivi, image to Nand Flash, SD Card.

With this case please calibrate the touchscreen again according following steps.
1. #rm /etc/pointercal
2. Reset the board
3. The system will show you a window with cross-point to calibrate the touchscreen

You need to prepare a logo image (png format), such as the name of linux_logo.png, please run under the linux: The settings are shown as the following directory.
# pngtopnm linux_logi.png > linux_logo.pnm
# pnmquant 224 linux_logo.pnm > linux_logo224.pnm
# pnmtoplainpnm linux_logo224.pnm > logo_linux_clut224.ppm
Finally will be generated a file of logo_linux_clut224.ppm, then replace the file in the directory "\drivers\video\logo\logo_linux_clut224.ppm", and begin to recompile.

Under the wince, users only need to choose according to their own LCD screen display resolution modify the macro definition of different screen in the file "bsp_cfg.h" under the directory "\SRC\INC". 
Under the linux QT, execute the command "make menuconfig" , then setting according to the following directory "Device Drivers --> Graphics support --> Support for frame buffer devices" , select the corresponding LCD screen LCD Type. Detailed methodology please refer to the corresponding user manual. 
Under the android, if you are switching between resistive screen, you can modify the parameters of LCD in the bootargs under the uboot environment variable. If you are switching between the resistive and capacitive touch panel screen, you need to execute "make menuconfig" in the kernel, then setting according to the following directory "Device Drivers --> Input device support --> Touchscreens" , select the appropriate option to configure.