See the top level README for information on where to find documentation for the raspberry pi and the ARM processor inside. Also find information on how to load and run these programs. These examples are for the pi3, see other directories for other flavors of raspberry pi. This directory is for aarch32 mode (dont use a config.txt) and switches from HYP back to SVC mode. The bootloader is one level up and shared for both SVC and HYP as I want the applications loaded to make the changes not the bootloader. For now this seems to work switching back to SVC and to secure mode .globl _start _start: ldr pc,reset_handler ldr pc,undefined_handler ldr pc,swi_handler ldr pc,prefetch_handler ldr pc,data_handler ldr pc,hyp_handler ldr pc,irq_handler ldr pc,fiq_handler reset_handler: .word reset undefined_handler: .word hang swi_handler: .word smc prefetch_handler: .word hang data_handler: .word hang hyp_handler: .word hang irq_handler: .word hang fiq_handler: .word hang reset: ;@ b skip mrs r0,cpsr bic r0,r0,#0x1F orr r0,r0,#0x13 msr spsr_cxsf,r0 add r0,pc,#4 msr ELR_hyp,r0 eret skip: mrc p15, 0, r1, c12, c0, 0 ;@ get vbar mov r0,#0x8000 ;@ mov r1,#0x0000 ldmia r0!,{r2,r3,r4,r5,r6,r7,r8,r9} stmia r1!,{r2,r3,r4,r5,r6,r7,r8,r9} ldmia r0!,{r2,r3,r4,r5,r6,r7,r8,r9} stmia r1!,{r2,r3,r4,r5,r6,r7,r8,r9} mov r12,#0 mcr p15, 0, r12, c7, c10, 1 dsb mov r12, #0 mcr p15, 0, r12, c7, c5, 0 mov r12, #0 mcr p15, 0, r12, c7, c5, 6 dsb isb smc #0 mrc p15,0,r2,c1,c0,0 bic r2,#0x1000 bic r2,#0x0004 mcr p15,0,r2,c1,c0,0 mov sp,#0x8000 mov r0,pc bl notmain hang: b hang smc: mrc p15, 0, r1, c1, c1, 0 bic r1, r1, #1 mcr p15, 0, r1, c1, c1, 0 movs pc, lr