Difference between revisions of "Bootx (iBoot command)"

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== Description ==
== iPhone 3GS 8920x from iBoot-636.66 ==
 
  +
A command found in [[iBEC]], [[iBoot]], and [[iBSS]] that verifies and boots a [[kernelcache]] image which has been uploaded.
 
==Disassembly==
 
<pre>
 
N88AP_iBoot:4FF007E8 n88ap__iBoot__bootx_function ; DATA XREF: N88AP_iBoot:n88ap__iBoot__bootx�o
 
N88AP_iBoot:4FF007E8
 
N88AP_iBoot:4FF007E8 kernelcache_prepped_memory_pos= -0x10
 
N88AP_iBoot:4FF007E8 oldR4 = -0xC
 
N88AP_iBoot:4FF007E8 oldR7 = -8
 
N88AP_iBoot:4FF007E8 oldLR = -4
 
N88AP_iBoot:4FF007E8
 
N88AP_iBoot:4FF007E8 000 PUSH {R4,R7,LR} ; Push registers
 
N88AP_iBoot:4FF007EA 00C ADD R7, SP, #4 ; Rd = Op1 + Op2
 
N88AP_iBoot:4FF007EC 00C SUB SP, SP, #4 ; Rd = Op1 - Op2
 
N88AP_iBoot:4FF007EE 010 CMP R0, #1 ; Set cond. codes on Op1 - Op2
 
N88AP_iBoot:4FF007F0 010 MOV R4, R1 ; Rd = Op2
 
N88AP_iBoot:4FF007F2 010 BLE loc_4FF00808 ; Branch
 
N88AP_iBoot:4FF007F4 010 LDR R1, [R1,#0x24] ; argv[1]
 
N88AP_iBoot:4FF007F6 010 LDR R0, =aHelp ; "help"
 
N88AP_iBoot:4FF007F8 010 BL strcmp ; Branch with Link
 
N88AP_iBoot:4FF007FC 010 CBNZ R0, loc_4FF00808 ; Compare and Branch on Non-Zero
 
N88AP_iBoot:4FF007FE 010 LDR R1, [R4,#0x10] ; param_R1
 
N88AP_iBoot:4FF00800 010 LDR R0, =aUsageSAddress ; "usage:\n\t%s [<address>]\n"
 
N88AP_iBoot:4FF00802 010 BL N88AP__iBOOT__console_printf ; Branch with Link
 
N88AP_iBoot:4FF00806 010 B loc_4FF0081C ; Branch
 
N88AP_iBoot:4FF00808 ; ---------------------------------------------------------------------------
 
N88AP_iBoot:4FF00808
 
N88AP_iBoot:4FF00808 loc_4FF00808 ; CODE XREF: n88ap__iBoot__bootx_function+A�j
 
N88AP_iBoot:4FF00808 ; n88ap__iBoot__bootx_function+14�j
 
N88AP_iBoot:4FF00808 010 MOV.W R0, #n88ap_ramdisk ; addr
 
N88AP_iBoot:4FF0080C 010 MOV.W R1, #0xF00000 ; size
 
N88AP_iBoot:4FF00810 010 BL check_range ; Branch with Link
 
N88AP_iBoot:4FF00814 010 CBNZ R0, loc_4FF00822 ; Compare and Branch on Non-Zero
 
N88AP_iBoot:4FF00816 010 LDR R0, =aPermissionDenied ; "Permission Denied\n"
 
N88AP_iBoot:4FF00818 010 BL N88AP__iBOOT__console_printf ; Branch with Link
 
N88AP_iBoot:4FF0081C
 
N88AP_iBoot:4FF0081C loc_4FF0081C ; CODE XREF: n88ap__iBoot__bootx_function+1E�j
 
N88AP_iBoot:4FF0081C 010 MOV.W R4, #0xFFFFFFFF ; fail
 
N88AP_iBoot:4FF00820 010 B loc_4FF0085C ; Branch
 
N88AP_iBoot:4FF00822 ; ---------------------------------------------------------------------------
 
N88AP_iBoot:4FF00822
 
N88AP_iBoot:4FF00822 loc_4FF00822 ; CODE XREF: n88ap__iBoot__bootx_function+2C�j
 
N88AP_iBoot:4FF00822 010 MOV.W R1, #n88ap_ramdisk ; param_R1
 
N88AP_iBoot:4FF00826 010 LDR R0, =aAttemptingToValidateKernelcache0x08x ; "Attempting to validate kernelcache @ 0x"...
 
N88AP_iBoot:4FF00828 010 BL N88AP__iBOOT__console_printf ; Branch with Link
 
N88AP_iBoot:4FF0082C 010 MOV.W R0, #n88ap_ramdisk ; memoery_pos
 
N88AP_iBoot:4FF00830 010 MOV.W R1, #0xF00000 ; memory_size
 
N88AP_iBoot:4FF00834 010 MOV R2, SP ; Rd = Op2
 
N88AP_iBoot:4FF00836 010 BL LoadImage_kernelcache_img3 ; Branch with Link
 
N88AP_iBoot:4FF0083A 010 CMP R0, #0 ; Set cond. codes on Op1 - Op2
 
N88AP_iBoot:4FF0083C 010 MOV R4, R0 ; Rd = Op2
 
N88AP_iBoot:4FF0083E 010 BGE loc_4FF00848 ; Branch
 
N88AP_iBoot:4FF00840 010 LDR R0, =aErrorLoadingKernelcache ; "error loading kernelcache\n"
 
N88AP_iBoot:4FF00842 010 BL N88AP__iBOOT__console_printf ; Branch with Link
 
N88AP_iBoot:4FF00846 010 B loc_4FF0085C ; Branch
 
N88AP_iBoot:4FF00848 ; ---------------------------------------------------------------------------
 
N88AP_iBoot:4FF00848
 
N88AP_iBoot:4FF00848 loc_4FF00848 ; CODE XREF: n88ap__iBoot__bootx_function+56�j
 
N88AP_iBoot:4FF00848 010 LDR R1, [SP,#0x10+kernelcache_prepped_memory_pos] ; param_R1
 
N88AP_iBoot:4FF0084A 010 LDR R0, =aKernelcachePreppedAtAddress0x08x ; "kernelcache prepped at address 0x%08x\n"
 
N88AP_iBoot:4FF0084C 010 BL N88AP__iBOOT__console_printf ; Branch with Link
 
N88AP_iBoot:4FF00850 010 LDR R2, =dword_4FF2DC40 ; Load from Memory
 
N88AP_iBoot:4FF00852 010 MOVS R0, #3 ; Rd = Op2
 
N88AP_iBoot:4FF00854 010 LDR R1, [SP,#0x10+kernelcache_prepped_memory_pos] ; Load from Memory
 
N88AP_iBoot:4FF00856 010 LDR R2, [R2] ; Load from Memory
 
N88AP_iBoot:4FF00858 010 BL jump_to_addr ; Branch with Link
 
N88AP_iBoot:4FF0085C
 
N88AP_iBoot:4FF0085C loc_4FF0085C ; CODE XREF: n88ap__iBoot__bootx_function+38�j
 
N88AP_iBoot:4FF0085C ; n88ap__iBoot__bootx_function+5E�j
 
N88AP_iBoot:4FF0085C 010 MOV R0, R4 ; Rd = Op2
 
N88AP_iBoot:4FF0085E 010 SUB.W SP, R7, #4 ; Rd = Op1 - Op2
 
N88AP_iBoot:4FF00862 010 POP {R4,R7,PC} ; Pop registers
 
N88AP_iBoot:4FF00862 ; End of function n88ap__iBoot__bootx_function
 
N88AP_iBoot:4FF00862
 
N88AP_iBoot:4FF00862 ; ---------------------------------------------------------------------------
 
N88AP_iBoot:4FF00864 off_4FF00864 DCD aHelp ; DATA XREF: n88ap__iBoot__bootx_function+E�r
 
N88AP_iBoot:4FF00864 ; "help"
 
N88AP_iBoot:4FF00868 ; int off_4FF00868
 
N88AP_iBoot:4FF00868 off_4FF00868 DCD aUsageSAddress ; DATA XREF: n88ap__iBoot__bootx_function+18�r
 
N88AP_iBoot:4FF00868 ; "usage:\n\t%s [<address>]\n"
 
N88AP_iBoot:4FF0086C ; int off_4FF0086C
 
N88AP_iBoot:4FF0086C off_4FF0086C DCD aPermissionDenied ; DATA XREF: n88ap__iBoot__bootx_function+2E�r
 
N88AP_iBoot:4FF0086C ; "Permission Denied\n"
 
N88AP_iBoot:4FF00870 ; int off_4FF00870
 
N88AP_iBoot:4FF00870 off_4FF00870 DCD aAttemptingToValidateKernelcache0x08x
 
N88AP_iBoot:4FF00870 ; DATA XREF: n88ap__iBoot__bootx_function+3E�r
 
N88AP_iBoot:4FF00870 ; "Attempting to validate kernelcache @ 0x"...
 
N88AP_iBoot:4FF00874 ; int off_4FF00874
 
N88AP_iBoot:4FF00874 off_4FF00874 DCD aErrorLoadingKernelcache
 
N88AP_iBoot:4FF00874 ; DATA XREF: n88ap__iBoot__bootx_function+58�r
 
N88AP_iBoot:4FF00874 ; "error loading kernelcache\n"
 
N88AP_iBoot:4FF00878 ; int off_4FF00878
 
N88AP_iBoot:4FF00878 off_4FF00878 DCD aKernelcachePreppedAtAddress0x08x
 
N88AP_iBoot:4FF00878 ; DATA XREF: n88ap__iBoot__bootx_function+62�r
 
N88AP_iBoot:4FF00878 ; "kernelcache prepped at address 0x%08x\n"
 
N88AP_iBoot:4FF0087C off_4FF0087C DCD dword_4FF2DC40 ; DATA XREF: n88ap__iBoot__bootx_function+68�r
 
</pre>
 
   
 
==Decompliation==
 
==Decompliation==
  +
===[[N88AP|iPhone 3GS]] S5L8920x from [[iBoot-636.66]]===
<pre>
 
#define kLoadAddress 0x41000000
+
#define kLoadAddress 0x41000000
#define kKernelMaxSize 0xF00000
+
#define kKernelMaxSize 0xF00000
  +
 
  +
char** gBootArgs;
int cmd_bootx(int argc, CmdArg* argv) {
 
  +
  +
int cmd_bootx(int argc, [[CmdArg]]* argv) {
 
void* address = NULL;
 
void* address = NULL;
 
if(argc > 1 && !strcmp("help", argv[1].string)) {
 
if(argc > 1 && !strcmp("help", argv[1].string)) {
Line 125: Line 32:
 
 
 
return err;
 
return err;
}
+
}
</pre>
 

Latest revision as of 08:37, 13 October 2015

Description

A command found in iBEC, iBoot, and iBSS that verifies and boots a kernelcache image which has been uploaded.

Decompliation

iPhone 3GS S5L8920x from iBoot-636.66

#define kLoadAddress 0x41000000
#define kKernelMaxSize 0xF00000

char** gBootArgs;

int cmd_bootx(int argc, CmdArg* argv) {
   void* address = NULL;
   if(argc > 1 && !strcmp("help", argv[1].string)) {
       printf("usage:\n\t%s [<address>]\n", argv[0].string);
       return -1;
   }
   
   if(range_check(kLoadAddress, kKernelMaxSize) < 0) {
       printf("Permission Denied\n");
       return -1;
   }
   
   printf("Attempting to validate kernelcache @ 0x%08x\n", kLoadAddress);
   int err = load_macho_image(kLoadAddress, kKernelMaxSize, &address)
   if(err >= 0) {
       printf("kernelcache prepped at address 0x%08x\n", address);
       jump_to(3, address, gBootArgs);
       
   } else {
       printf("error loading kernelcache\n");
   }
   
   return err;
}