If you followed the procedure to save the original flash ROM shipped with your iPAQ, you can restore Windows CE. (These instructions based on the instructions provided by Handhelds.org. See iPAQ PocketPC (WinCE) Restoration Project.)
This procedure does not save your Linux configuration or any data you may have created while using Linux. Back up whatever data you need before starting this procedure.
Improper restoration could render your iPAQ unusable. Follow all instructions exactly as shown.
You must have a terminal emulation program that supports XModem file transfers. Configure your terminal emulator with the following settings:
Make sure you have the following four Windows CE flash ROM files available:
Because of the limitations of the XModem protocol, you can expect somewhat long transfer times for the following procedures. Expect the installation to take 40 minutes to an hour. After loading each file, you will see the bootldr program erase the flash, write the new data, and verify the flash ROM.
Restart the iPAQ and immediately press the space bar in your terminal emulator. Pressing the space bar should interrupt the boot loader and give you a boot> prompt.
If you don't get a boot> prompt and the iPAQ loads Linux, repeat Step 1, pressing the space bar quickly several times.
At the prompt, enter 'load flash 0x00c00000' and use XModem to send flash_00c00000.bin to the iPAQ.
At the prompt, enter 'load flash 0x00800000' and use XModem to send flash_00800000.bin to the iPAQ.
At the prompt, enter 'load flash 0x00400000' and use XModem to send flash_00400000.bin to the iPAQ.
At the prompt, enter the following two commands:
set override 1 pflash 0x0 0x0 0
At the prompt, enter 'load flash 0x0' and use XModem to send flash_00000000.bin to the iPAQ.
Wait until you see boot> prompt and restart the iPAQ.
Click the Self Test tab.
Check ROM checksum. You might want to uncheck the other tests.
Check Perform automatic 'Reset' before test, and click Start.
If you see "pass" in the Status column for the ROM checksum, you have successfully restored Windows CE.