fixed potential crash, when chunk size is greater than block size
fixed potential crash, when chunk size is greater than block size

chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI,chriz2600/DreamcastHDMI