code: public DfuServiceInitiator setCustomUuidsForLegacyDfu(@Nullable final UUID dfuServiceUuid,
  														  @Nullable final UUID dfuControlPointUuid,
  														  @Nullable final UUID dfuPacketUuid,
  														  @Nullable final UUID dfuVersionUuid) {
  		final ParcelUuid[] uuids = new ParcelUuid[4];
  		uuids[0] = dfuServiceUuid      != null ? new ParcelUuid(dfuServiceUuid)      : null;
  		uuids[1] = dfuControlPointUuid != null ? new ParcelUuid(dfuControlPointUuid) : null;
  		uuids[2] = dfuPacketUuid       != null ? new ParcelUuid(dfuPacketUuid)       : null;
  		uuids[3] = dfuVersionUuid      != null ? new ParcelUuid(dfuVersionUuid)      : null;
  		legacyDfuUuids = uuids;
  		return this;
  	}
docs: Sets custom UUIDs for Legacy DFU and Legacy Buttonless DFU. Use this method if your DFU
  implementation uses different UUID for at least one of the given UUIDs.
  Parameter set to <code>null</code> will reset the UUID to the default value.
  
  @param dfuServiceUuid      custom Legacy DFU service UUID or null, if default is to be used
  @param dfuControlPointUuid custom Legacy DFU Control Point characteristic UUID or null,
  if default is to be used
  @param dfuPacketUuid       custom Legacy DFU Packet characteristic UUID or null, if default is
  to be used
  @param dfuVersionUuid      custom Legacy DFU Version characteristic UUID or null,
  if default is to be used (SDK 7.0 - 11.0 only, set null for earlier SDKs)
  @return the builder