diff --git a/source/common/bootfirm.h b/source/common/bootfirm.h
new file mode 100644
index 0000000..b1dc441
--- /dev/null
+++ b/source/common/bootfirm.h
@@ -0,0 +1,4 @@
+#pragma once
+#include "common.h"
+
+void __attribute__((noreturn)) BootFirm(void *firm, char *path);
diff --git a/source/common/bootfirm.s b/source/common/bootfirm.s
new file mode 100644
index 0000000..10eaf38
--- /dev/null
+++ b/source/common/bootfirm.s
@@ -0,0 +1,151 @@
+.section .text
+.arm
+.align 4
+
+.equ ARG_MAGIC, 0xBEEF
+.equ MPCORE_LD, 0x27FFFB00
+.equ STUB_LOC,  0x27FFFC00
+.equ FBPTR_LOC, 0x23FFFE00
+.equ ARGV_LOC,  0x23FFFE20
+
+.cpu mpcore
+MPCore_stub:
+    mov r0, #0x20000000
+    mov r1, #0
+    str r1, [r0, #-4]
+    .Lcheckmpcentry:
+        ldr r1, [r0, #-4]
+        cmp r1, #0
+        beq .Lcheckmpcentry
+    bx r1
+.pool
+MPCore_stub_end:
+
+@ Assume these functions ALWAYS clobber R0-R3 and R12 and don't use the stack
+.equ MEMCPY,   0xFFFF0374 @ void memcpy32(void *src, void *dest, u32 size)
+.equ INV_DC,   0xFFFF07F0 @ void invalidate_dcache(void)
+.equ WB_DC,    0xFFFF07FC @ void writeback_dcache(void)
+.equ WBINV_DC, 0xFFFF0830 @ void writeback_invalidate_dcache(void)
+.equ INV_IC,   0xFFFF0AB4 @ void invalidate_icache(void)
+.equ INITCP15, 0xFFFF0C58 @ void reset_cp15(void)
+
+.cpu arm946e-s
+@ void BootFirm_stub(void *firm, char *path)
+@ r0-r8: scratch registers
+@ r9: FIRM path
+@ r10: FIRM header
+@ r11: current section header
+BootFirm_stub:
+    mov r10, r0
+    add r11, r0, #0x40
+    mov r9, r1
+
+    mov r4, #4
+    .LBootFirm_stub_copysect:
+        @ Fetch source, destination and length
+        ldmia r11, {r0-r2}
+
+        cmp r2, #0    @ If section is unused/zerolength, don't even bother
+        addne r0, r10 @ Fix source address
+
+        ldrne r3, =MEMCPY
+        blxne r3
+
+        subs r4, #1
+        addne r11, #0x30 @ Advance to the next section
+        bne .LBootFirm_stub_copysect
+
+    @ Boot state
+        @ CPSR:
+        @ ARM, Supervisor, IRQ/FIQs disabled
+        @ Flags are undefined
+        msr cpsr_c, #0xD3
+
+        @ CP15:
+        @ MPU and Caches are off
+        @ TCMs are on (location/configuration is undefined)
+        @ Alternative exception vectors are enabled (0xFFFF0000)
+        ldr r3, =WBINV_DC
+        ldr r4, =INV_IC
+        ldr r5, =INITCP15
+        blx r3
+        blx r4
+        blx r5
+
+        @ Registers:
+        @ R0 = 0x00000002
+        @ R1 = 0x23FFFE10
+        @ R2 = 0x0000BEEF
+        @ R3-R14 are undefined
+
+        mov r0, #2
+        ldr r1, =ARGV_LOC
+        ldr r2, =ARG_MAGIC
+
+
+    @ Setup argv
+    str r9, [r1, #0x00] @ FIRM path / argv[0]
+
+    ldr r3, =FBPTR_LOC
+    str r3, [r1, #0x04] @ Framebuffers / argv[1]
+
+    @ Fetch FIRM entrypoints
+    ldr r3, [r10, #0x08] @ ARM11 entrypoint
+    ldr r4, [r10, #0x0C] @ ARM9 entrypoint
+
+    @ Set the ARM11 entrypoint
+    mov r5, #0x20000000
+    str r3, [r5, #-4]
+
+    @ Branch to the ARM9 entrypoint
+    bx r4
+
+.pool
+BootFirm_stub_end:
+
+@ void BootFirm(void *firm, char *path)
+@ BootFirm_stub wrapper
+@ No checks are performed on the data
+.global BootFirm
+.type BootFirm, %function
+BootFirm:
+    mov r10, r0
+
+    @ Copy the FIRM path somewhere safe
+    ldr r0, =(ARGV_LOC+8)
+    mov r11, r0
+    blx strcpy
+
+    @ Relocate the MPCore stub binary
+    ldr r4, =MPCORE_LD
+    adr r1, MPCore_stub
+    adr r2, MPCore_stub_end
+    sub r2, r1
+    mov r0, r4
+    blx memcpy
+
+    @ Make the ARM11 run the stub, wait until its done
+    mov r1, #0x20000000
+    mov r0, r4
+    str r0, [r1, #-4]
+    .Lwaitforsi:
+        ldr r0, [r1, #-4]
+        cmp r0, #0
+        bne .Lwaitforsi
+
+    @ Relocate BootFirm
+    ldr r4, =STUB_LOC
+    adr r5, BootFirm_stub
+    adr r6, BootFirm_stub_end
+    sub r7, r6, r5
+
+    mov r0, r4
+    mov r1, r5
+    mov r2, r7
+    blx memcpy
+
+    mov r0, r10
+    mov r1, r11
+
+    bx r4
+    b .
diff --git a/source/common/chainload.h b/source/common/chainload.h
index 7b2dc1d..123cfa3 100644
--- a/source/common/chainload.h
+++ b/source/common/chainload.h
@@ -4,4 +4,5 @@
 
 #define PAYLOAD_MAX_SIZE 0xFFFE0
 
-void Chainload(u8 *source, size_t size);
+void __attribute__((noreturn)) Chainload(u8 *source, size_t size);
+void __attribute__((noreturn)) BootFirm(FirmHeader *firm, char *path);
diff --git a/source/game/firm.c b/source/game/firm.c
index c04ccff..7512d26 100644
--- a/source/game/firm.c
+++ b/source/game/firm.c
@@ -9,6 +9,14 @@
 // 0 -> pre 9.5 / 1 -> 9.5 / 2 -> post 9.5
 #define A9L_CRYPTO_TYPE(hdr) ((hdr->k9l[3] == 0xFF) ? 0 : (hdr->k9l[3] == '1') ? 1 : 2)
 
+// valid addresses for FIRM section loading, pairs of start / end address, provided by Wolfvak
+#define FIRM_VALID_ADDRESS  \
+    0x08006000, 0x08800000, \
+    0x18000000, 0x18600000, \
+    0x1FFF0000, 0x1FFFFFFC, \
+    0x20000000, 0x23FFFE00, \
+    0x24000000, 0x27FFFB00
+
 u32 ValidateFirmHeader(FirmHeader* header, u32 data_size) {
     u8 magic[] = { FIRM_MAGIC };
     if (memcmp(header->magic, magic, sizeof(magic)) != 0)
@@ -21,6 +29,7 @@ u32 ValidateFirmHeader(FirmHeader* header, u32 data_size) {
         FirmSectionHeader* section = header->sections + i;
         if (!section->size) continue;
         if (section->offset < firm_size) return 1;
+        if ((section->offset % 512) || (section->address % 512) || (section->size % 512)) return 1;
         if ((header->entry_arm11 >= section->address) &&
             (header->entry_arm11 < section->address + section->size))
             section_arm11 = i;
@@ -50,6 +59,36 @@ u32 ValidateFirmA9LHeader(FirmA9LHeader* header) {
     return sha_cmp((IS_DEVKIT) ? enckeyX0x15devhash : enckeyX0x15hash, header->keyX0x15, 0x10, SHA256_MODE);
 }
 
+u32 ValidateFirm(void* firm, u32 firm_size) {
+    FirmHeader* header = (FirmHeader*) firm;
+    
+    // validate firm header
+    if (ValidateFirmHeader(header, firm_size) != 0)
+        return 1;
+    
+    // hash verify all available sections and check load address
+    for (u32 i = 0; i < 4; i++) {
+        u32 valid_address[] = { FIRM_VALID_ADDRESS };
+        FirmSectionHeader* section = header->sections + i;
+        if (!section->size) continue;
+        if (sha_cmp(section->hash, (u8*) firm + section->offset, section->size, SHA256_MODE) != 0) {
+            return 1;
+        }
+        bool is_valid_address = false;
+        for (u32 a = 0; a < sizeof(valid_address) / (2*sizeof(u32)); a++) {
+            if ((valid_address[2*a] >= section->address) && (valid_address[(2*a)+1] <= section->address + section->size))
+                is_valid_address = true;
+        }
+        if (!is_valid_address) return 1;
+    }
+    
+    // section for arm9 entrypoint not found?
+    if (!FindFirmArm9Section(header))
+        return 1;
+    
+    return 0;
+}
+
 FirmSectionHeader* FindFirmArm9Section(FirmHeader* firm) {
     for (u32 i = 0; i < 4; i++) {
         FirmSectionHeader* section = firm->sections + i;
diff --git a/source/game/firm.h b/source/game/firm.h
index da53cf5..8d812be 100644
--- a/source/game/firm.h
+++ b/source/game/firm.h
@@ -43,6 +43,7 @@ typedef struct {
 
 u32 ValidateFirmHeader(FirmHeader* header, u32 data_size);
 u32 ValidateFirmA9LHeader(FirmA9LHeader* header);
+u32 ValidateFirm(void* firm, u32 firm_size);
 
 FirmSectionHeader* FindFirmArm9Section(FirmHeader* firm);
 u32 GetArm9BinarySize(FirmA9LHeader* a9l);
diff --git a/source/godmode.c b/source/godmode.c
index 9b85857..5d6e05a 100644
--- a/source/godmode.c
+++ b/source/godmode.c
@@ -1417,11 +1417,15 @@ u32 FileHandlerMenu(char* current_path, u32* cursor, u32* scroll, DirStruct* cur
         }
         return 0;
     } else if ((user_select == boot)) {
-        size_t payload_size = FileGetSize(curr_entry->path);
-        if (ShowUnlockSequence(3, "%s (%dkB)\nBoot FIRM via boot9strap?\n(requires boot9strap nightly)", pathstr, payload_size / 1024)) {
-            u32 flags = OVERWRITE_ALL;
-            if (PathMoveCopy("0:/bootonce.firm", curr_entry->path, &flags, false))
-                Reboot();
+        size_t firm_size = FileGetSize(curr_entry->path);
+        if (firm_size > TEMP_BUFFER_SIZE) {
+            ShowPrompt(false, "FIRM too big, can't launch"); // unlikely
+        } else if (ShowUnlockSequence(3, "%s (%dkB)\nBoot FIRM via chainloader?", pathstr, firm_size / 1024)) {
+            if ((FileGetData(curr_entry->path, TEMP_BUFFER, firm_size, 0) == firm_size) &&
+                (ValidateFirm(TEMP_BUFFER, firm_size) != 0)) {
+                BootFirm((FirmHeader*)(void*)TEMP_BUFFER, curr_entry->path);
+                while(1);
+            } else ShowPrompt(false, "Not a vaild FIRM, can't launch");
         }
         return 0;
     } else if ((user_select == script)) {