When using a cape with an unsigned EEPROM, the BBB48String, BBShiftString, and DPIPixels Channel Outputs are limited to 50 pixels max per string output and are not allowed to use differential smart receivers. Sensor functionality may be limited as well. If you apply a license key or keys to sign the EEPROM, these limits are removed for the number of outputs covered by the license key(s) applied. The covered outputs are ALWAYS applied starting at the first outputs on a board, you can not select which outputs to cover with a license key.