We've found that tones created while using the original 1.01 firmware can sometimes be corrupted, regardless if they are new or downloaded tones. This results in the device locking up, with a factory reset being needed for recovery (press and hold the Master Volume knob and the TAP button as you power up the unit).
Firmwares at version 1.10 or later resolves this issue. Tones created in version 1.10 or later can no longer be corrupted like they would have under version 1.01. However, corrupted tones created in version 1.01 are still problematic when used in Firehawks updated to later firmware versions.
We encourage those encountering this issue to update to the latest firmware via the Line 6 Updater software, then perform a factory reset. Please note that any tones not backed up to My Tones prior to a reset will be lost (corrupted tones cannot be uploaded because they crash the unit and thus can't be selected for uploading).