Automotive Bootloader Concept & Basic Primary Bootloader, Secondary Bootloader, Application to Bootloader Jump, Boot to Application Jump. Programing Sequence and Reprogramming sequence.

1. Automotive
Bootloader
From Tech Agile

2. Purpose of Bootloader
Update the Application
• Add new Features
• Remove Bugs
Update Bootloader
• Add new Features
• Remove Bugs
Exchange of Informationwith Application

3. Type of Bootloader
Single Level Bootloader
• Primary Bootloader, There is not Secondary Bootloader (PBL)
• Primary Bootloader will be placed in Flash Memory, which is required to be
flashed using debugger.
Two Level Bootloader
• Primary and Secondary Bootloader both are available (SBL)
• PBL is required to be flashed using Debugger, It will be placed in Flash
Memory of the controller
• SBL can be loaded into RAM Area using PBL.

4. Type of Bootloader
1. Download Over CAN, LIN, FlexRay, Ethernet (DOIP)
❑ We use UDS services to Transfer the data over the bus
2. Download Over Serial Bus

5. Single Level Bootloader
ISystem - WinIDEA Debugger

6. Two Level Bootloader

7. Advantage of Two Level Bootloader
• SBL will be loaded into RAM Memory, which will not be accessing after
successfulApplication, which make is more secure.
• Many of Controller will not support Flash to Flash erase and Programming, in
such condition, Two Level Bootloader is necessary
• Assume there is bug in Bootloader, and because of which we can’t
download/update the applicable which make the ECU non usable.
• Special SBL will be capable to updating PBL as well using which we can resolve
bug of PBL as well.

8. Where does Bootloader Reside ?
SBL
PBL
Application
Memory
ECU

9. Flash Memory
• PBL can contain multiple block of Flash Memory. Each Block is required to be
flashed correctly.
• SBL can also have multiple blocks. Each Block is required to be flashed
correctly.
• Application can also have multiple blocks. In most cases, definitely app will
have more numbers of block. Each Block is required to validated before
Flashing into memory. Unlock of ECU, CRC Check and ECU specific Application
Validated is required.

10. Where does Bootloader Reside ?
PBL
Application
Memory
ECU
SBL
SBL
SBL
PBL
Application
Application
Application

11. Memory Alignment
• You always need to Erase the Complete block of Memory, controller doesn’t
support erase of only specific bytes in most cases.
• Read and write of only specific bytes is possible, However it will depends on
controller alignment for read and write operation.

12. Flash Memory
• Signal Database: Generally there will be separate block for Signal Database,
where all the CAN, LIN Signal will be stored.
• Fault Memory: DTS Information and Snapshot Record will be stored in Flash
Memory at specified address.

13. Communication Bootloader <-> APP
• Bootloader need to give controller to Application once Validation Application
is successful.
• Application need to communicationwith Bootloader in case of Application
update is require, while valid application is running.
❑ This is case of Reprogramming
Bootloader Application
Flag Set/Clear

14. Download Sequence
Programming or
Reprogramming
Session Request
: 10 02
/10 80
Security
Access to
Unlock the ECU
OEM Specific
Read Data By
Identified or
other
diagnostic
request
Erase Request
using Routine
Control or
other
diagnostic
service
Programming
Request
Download Request :
0x34
Data Transfer :
0x36
Transfer Exit :
0x37
OEM
Specific
Application
Validation
ECU Reset

15. Download Sequence
Prog Session Req
Security Access
PBL
Erase
Application
SBL
Program
Application
ECU Reset

16. Startup Sequence
Power on Self Test
Startup Code
PBL
Application
No ValidApp Present
ValidApp Present
• Stack Pointer
Initialization
• RAM Initialization
• Jump to PBL