Dell P29T Service Manual page 97

Question
You successfully recovered your Chromebook but now you can not
use your USB or SD card with Windows
You successfully recovered your Chromebook but now Windows
does not recognize the whole size of the USB or SD card used for
recover.
Solution
After you have completed recovery, you need to format your USB
or SD card using the recovery tool.
After you have completed recovery, you need to format your USB
or SD card using the recovery tool.
Troubleshooting 97