This article should only be used on older HC1 units whose model number sticker inside the battery compartment shows HC1-xxxxxADG (where xxxxx are various characters). Do not use this article on HC1-xxxxxMDG units.
You will need a Micro SD card, minimum 256MB and maximum 32GB.
The Micro SD slot is on the side of the device. Remove the cover with a small Phillips screwdriver. Insert the card with the metallic end first. If it sticks, don't force it. Flip it over and try the other way.
Download, save, and extract the file from http://dl.waspbarcode.com/kb/mobiledevice/hc1/hc1-adg-v1.01.05.zip
Copy the file FLASH.BIN to the Micro SD card (or SDMMC). Note: Do not copy to Flash Storage, which is not the same as the SD card.
This can be done either through a card reader attached to the PC, or with the SD card loaded into the HC1 using Windows Mobile Device Center's "Browse the contents of your device".
Press and hold the left side top yellow trigger button. Keep holding until instructed to release.
With the stylus, press the reset button (hole to the right below the yellow trapezoid scan button on the keypad).
Watch the bottom of the screen. When you see the words Cold Boot in a black box, release the left trigger button.
Press the Down Arrow button. A gray menu should appear.
Arrow down to "SD update OS.", then press Enter key.
The download begins. The bottom of the screen shows a progress bar.
When the update finishes, the device will restart.