SAMA7D65 ready-made Buildroot images & BSR
Known Limitation with Backup Self-Refresh (BSR) low power mode on ready-made Buildroot images
Description
Backup-with-Self Refresh mode (BSR) is not supported in buildroot ready-made images version linux4microchip+sama7d65-2024.10 (aka: sama7d65-ea-1.0).
The buildroot ready made images named linux4sam-buildroot-sama7d65_curiosity-graphics-sama7d65-ea-1.0.img.bz2 and linux4sam-buildroot-sama7d65_curiosity-headless-sama7d65-ea-1.0.img.bz2 don't support BSR mode as this option is not selected in the at91bootstrap boot-loader binary.
Work around
Recompile at91boostrap choosing the defconfig file sama7d65_curiosity-bsrsd1_uboot_defconfig and following the procedure described in the AT91Bootstrap section.
or
Use the ready-made Yocto Project images named linux4sam-poky-sama7d65_curiosity-graphics-sama7d65-ea-1.0.img.bz2 and linux4sam-poky-sama7d65_curiosity-headless-sama7d65-ea-1.0.img.bz2 which contain the support for BSR pre-compiled.