Redundant boot is supported on OSPI
flash boot modes. ROM tries to boot SBL at the Region1 address and if it fails to
boot, then ROM tries to boot from the locations in the order Region1 → Region2 →
Region3 → Region4 until boot is successful.
Table 5-14
| Region |
Address |
| 1 |
0x0_0000 |
| 2 |
0x2_0000 |
| 3 |
0x4_0000 |
| 4 |
0x6_0000 |
Following are the failures which can lead to redundant boot:
- Certificate corruption, ex. Image size, hash of the image, extension IDs,
signature etc.
- Image corruption, ex. bit
corruption, byte corruption due to aging of the flash, external interferences
etc.
Note: AM261x supports max image size (without
certificate) of 952KB. In the case of encrypted images, the random string
of 32 bytes is added to the image. So, for encrypted images the maximum size
of the SBL image will be 974816 bytes. Successfully booted flash Image
offset Address is available at the address 0000x84100.