
**Mandatory.** Must be implemented by all devices.

Send NACK (Class=0,Type=14 if no boot-loader implemented)

This is the first event in the boot loader sequence. The node should stop all other activities when in boot loader mode. This also means that the node should not react on other events (commands) then the boot loader related.

 | Data byte | Description | 
 | :---------: | ----------- | 
 | 0 | The nickname for the node. | 
 | 1 | Code that select boot loader algorithm to use. | 
 | 2 | GUID byte 0 (MSB) | 
 | 3 | GUID byte 3 (MSB + 3) | 
 | 4 | GUID byte 5 (MSB + 5) | 
 | 5 | GUID byte 7 (MSB + 7) | 
 | 6 | Content of register 0x92, Page select MSB. | 
 | 7 | Content of register 0x93, Page select LSB. | 

The following format can be used for nodes on a Level II segment as a midway between a full Level II handling as specified in Class=1024 and Level I. 

 | Data byte | Description |
 | :---------: | ----------- | 
 | 0-15 | GUID. | 
 | 16   | Boot-loader algorithm code. |


**Boot-loader Codes**


 | Code | Algorithm               | 
 | :----: | ---------             | 
 | 0x00 | VSCP algorithm.         | 
 | 0x01 | Microchip PIC algorithm | 
 | 0x10 | Atmel AVR algorithm 0   | 
 | 0x20 | NXP ARM algorithm 0     | 
 | 0x30 | ST ARM algorithm 0      |
 | 0x40 | Freescale algorithm 0   |
 | 0x50 | Espressif algorithm 0   |
 | 0xF0-FE | User defined algorithms |
 | 0xFF | No bootloader available |

All other codes reserved.
