I had the hardware error : 0x48 No device found. The acer CustomerSupport asked me to take the chrome book to the hardware repair shop for checking the drive, which might be faulty. I just read the steps mentioned in this article can opened the back panel of the chrome book. Just checked the HD cable connection to the motherboard, just unplugged it and put it back. That's it and the chrome book is working fine now, I didn't need the recovery USB too. Thank you for posting this article on the chrome book