If device can't be manually re-set to factory defaults, than it's big crap.
And, if it's running on Windows CE 6.0, all it's configuration - means Registry - is stored in files on internal flash drive. You probably will agree that those files can't be repaired/re-written by a hard-reset, which only copies the stock Windows CE 6.0 system files from ROM to internal flash drive.
Hence, use repair service.
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