The AVRDUDE Manual needs an exhaustive list of error codes. For example, our error is:
avrdude: Device signature = 0x1e930c (probably t84)
avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed
To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "0xff"
avrdude: writing eeprom (1 bytes):