MidasBootloaderIncompatibleWithLinux¶

Introduction¶

The bootloader of the following devices is incompatible with upstream Linux:

• Galaxy SIII (GT-I9300)
• Galaxy SIII 4G (GT-I9305)
• Galaxy Note II (GT-N7100)
• Galaxy Note II 4G (GT-N7105)

When jumping to Linux, the booloader still has:

• the instruction cache on
• the data cache on
• the MMU on

Documentation/arm/booting.rst which is there since 2003 states that:

• "The MMU must be off."
• "Data cache must be off."

Supporting s-boot¶

To workaround that:

• to disable the caches
• to disable CONFIG_GCC_PLUGINS

However as the kernel evolved we need to patch it more and more:

• The patch disabling the caches "was not necessary on Linux 3.4":lkml.iu.edu/hypermail/linux/kernel/1212.1/02099.html
• Disabling CONFIG_GCC_PLUGINS was also not necessary on older kernel where the option was not even present