diff --git a/fusee/fusee-secondary/src/nxboot.c b/fusee/fusee-secondary/src/nxboot.c
index 9799d9140..eb97c5fe9 100644
--- a/fusee/fusee-secondary/src/nxboot.c
+++ b/fusee/fusee-secondary/src/nxboot.c
@@ -1,6 +1,7 @@
 #include "utils.h"
 #include "nxboot.h"
 #include "key_derivation.h"
+#include "package2.h"
 #include "loader.h"
 #include "splash_screen.h"
 #include "exocfg.h"
@@ -58,6 +59,9 @@ void nxboot_main(void) {
     /* Derive keydata. */
     derive_nx_keydata(MAILBOX_EXOSPHERE_CONFIGURATION->target_firmware);
     
+    /* Patch package2, adding thermosphere + custom KIPs. */
+    package2_patch((void *)loader_ctx->package2_loadfile.load_address);
+    
     /* Boot up Exosphere. */
     MAILBOX_NX_BOOTLOADER_IS_SECMON_AWAKE = 0;
     if (MAILBOX_EXOSPHERE_CONFIGURATION->target_firmware <= EXOSPHERE_TARGET_FIRMWARE_400) { 
diff --git a/fusee/fusee-secondary/src/package2.c b/fusee/fusee-secondary/src/package2.c
new file mode 100644
index 000000000..15a84fa65
--- /dev/null
+++ b/fusee/fusee-secondary/src/package2.c
@@ -0,0 +1,47 @@
+#include "utils.h"
+#include "package2.h"
+#include "se.h"
+
+void package2_decrypt(void *package2_address);
+void package2_add_thermosphere_section(void *package2_address);
+void package2_patch_kernel(void *package2_address);
+void package2_patch_ini1(void *package2_address);
+void package2_fixup_header_and_section_hashes(void *package2_address);
+
+void package2_patch(void *package2_address) {
+    /* First things first: Decrypt (TODO: Relocate?) Package2. */
+    package2_decrypt(package2_address);
+    
+    /* Modify Package2 to add an additional thermosphere section. */
+    package2_add_thermosphere_section(package2_address);
+    
+    /* Perform any patches we want to the NX kernel. */
+    package2_patch_kernel(package2_address);
+    
+    /* Perform any patches we want to the INI1 (This is where our built-in sysmodules will be added.) */
+    package2_patch_ini1(package2_address);
+    
+    /* Fix all necessary data in the header to accomodate for the new patches. */
+    package2_fixup_header_and_section_hashes(package2_address);
+}
+
+
+void package2_decrypt(void *package2_address) {
+    /* TODO */
+}
+
+void package2_add_thermosphere_section(void *package2_address) {
+    /* TODO */
+}
+
+void package2_patch_kernel(void *package2_address) {
+    /* TODO */
+}
+
+void package2_patch_ini1(void *package2_address) {
+    /* TODO */
+}
+
+void package2_fixup_header_and_section_hashes(void *package2_address) {
+    /* TODO */
+}
\ No newline at end of file
diff --git a/fusee/fusee-secondary/src/package2.h b/fusee/fusee-secondary/src/package2.h
new file mode 100644
index 000000000..11c0c367b
--- /dev/null
+++ b/fusee/fusee-secondary/src/package2.h
@@ -0,0 +1,37 @@
+#ifndef FUSEE_PACKAGE2_H
+#define FUSEE_PACKAGE2_H
+
+/* This is a library for patching Package2 prior to handoff to Exosphere. */
+
+#define MAGIC_PK21 (0x31324B50)
+#define PACKAGE2_SIZE_MAX 0x7FC000
+#define PACKAGE2_SECTION_MAX 0x3
+
+typedef struct {
+    union {
+        uint8_t ctr[0x10];
+        uint32_t ctr_dwords[0x4];
+    };
+    uint8_t section_ctrs[4][0x10];
+    uint32_t magic;
+    uint32_t entrypoint;
+    uint32_t _0x58;
+    uint8_t version_max; /* Must be > TZ value. */
+    uint8_t version_min; /* Must be < TZ value. */
+    uint16_t _0x5E;
+    uint32_t section_sizes[4];
+    uint32_t section_offsets[4];
+    uint8_t section_hashes[4][0x20];
+} package2_meta_t;
+
+typedef struct {
+    uint8_t signature[0x100];
+    union {
+        package2_meta_t metadata;
+        uint8_t encrypted_header[0x100];
+    };
+} package2_header_t;
+
+void package2_patch(void *package2_address);
+
+#endif
\ No newline at end of file