diff --git a/fusee/fusee-secondary/Makefile b/fusee/fusee-secondary/Makefile
index 51a408be4..c8caba6ce 100644
--- a/fusee/fusee-secondary/Makefile
+++ b/fusee/fusee-secondary/Makefile
@@ -89,7 +89,7 @@ export VPATH	:=	$(foreach dir,$(SOURCES),$(CURDIR)/$(dir)) \
 			$(foreach dir,$(DATA),$(CURDIR)/$(dir)) \
 			$(AMS)/exosphere $(AMS)/exosphere/warmboot $(AMS)/exosphere/program/rebootstub \
 			$(AMS)/thermosphere $(AMS)/fusee/fusee-primary $(AMS)/sept/sept-primary \
-			$(AMS)/sept/sept-secondary $(AMS)/emummc $(AMS)/mesosphere/kernel_ldr $(KIPDIRS)
+			$(AMS)/sept/sept-secondary $(AMS)/emummc $(AMS)/mesosphere $(AMS)/mesosphere/kernel_ldr $(KIPDIRS)
 
 export DEPSDIR	:=	$(CURDIR)/$(BUILD)
 
@@ -100,7 +100,7 @@ KIPFILES 	:=	loader.kip ncm.kip pm.kip sm.kip ams_mitm.kip spl.kip boot.kip
 BINFILES	:=	$(foreach dir,$(DATA),$(notdir $(wildcard $(dir)/*.*))) fusee-primary.bin \
 				exosphere.bin warmboot.bin rebootstub.bin thermosphere.bin splash_screen.bmp \
 				sept-primary.bin sept-secondary_00.enc sept-secondary_01.enc emummc.kip \
-				sept-secondary_dev_00.enc sept-secondary_dev_01.enc kernel_ldr.bin $(KIPFILES)
+				sept-secondary_dev_00.enc sept-secondary_dev_01.enc mesosphere.bin kernel_ldr.bin $(KIPFILES)
 
 #---------------------------------------------------------------------------------
 # use CXX for linking C++ projects, CC for standard C
diff --git a/fusee/fusee-secondary/src/kernel_patches.c b/fusee/fusee-secondary/src/kernel_patches.c
index fc2451052..f61bf7e95 100644
--- a/fusee/fusee-secondary/src/kernel_patches.c
+++ b/fusee/fusee-secondary/src/kernel_patches.c
@@ -963,11 +963,6 @@ void package2_patch_kernel(void *_kernel, size_t *kernel_size, bool is_sd_kernel
     }
 
     if (kernel_info == NULL && is_sd_kernel) {
-        /* If the kernel is mesosphere, patch it. */
-        if (*(volatile uint32_t *)((uintptr_t)_kernel + 4) == 0x3053534D) {
-            *out_ini1 = (void *)((uintptr_t)_kernel + *(volatile uint32_t *)((uintptr_t)_kernel + 8));
-            *(volatile uint64_t *)((uintptr_t)_kernel + 8) = (uint64_t)*kernel_size;
-        }
         return;
     }
 
diff --git a/fusee/fusee-secondary/src/nxboot.c b/fusee/fusee-secondary/src/nxboot.c
index 7a8519208..b333157c0 100644
--- a/fusee/fusee-secondary/src/nxboot.c
+++ b/fusee/fusee-secondary/src/nxboot.c
@@ -633,6 +633,8 @@ uint32_t nxboot_main(void) {
     void *warmboot_memaddr;
     void *package1loader;
     size_t package1loader_size;
+    void *mesosphere;
+    size_t mesosphere_size;
     void *emummc;
     size_t emummc_size;
     uint32_t available_revision;
@@ -928,6 +930,28 @@ uint32_t nxboot_main(void) {
             pmc->scratch1 = (uint32_t)warmboot_memaddr;
     }
 
+    /* Configure mesosphere. */
+    /* TODO: Support non-SD/embedded mesosphere. */
+    {
+        size_t sd_meso_size = get_file_size("atmosphere/mesosphere.bin");
+        if (sd_meso_size != 0) {
+            if (sd_meso_size > PACKAGE2_SIZE_MAX) {
+                fatal_error("Error: atmosphere/kernel.bin is too large!\n");
+            }
+            mesosphere = malloc(sd_meso_size);
+            if (mesosphere == NULL) {
+                fatal_error("Error: failed to allocate mesosphere!\n");
+            }
+            if (read_from_file(mesosphere, sd_meso_size, "atmosphere/mesosphere.bin") != sd_meso_size) {
+                fatal_error("Error: failed to read atmosphere/mesosphere.bin!\n");
+            }
+            mesosphere_size = sd_meso_size;
+        } else {
+            mesosphere = NULL;
+            mesosphere_size = 0;
+        }
+    }
+
     print(SCREEN_LOG_LEVEL_INFO, "[NXBOOT] Rebuilding package2...\n");
 
     /* Parse stratosphere config. */
@@ -936,7 +960,7 @@ uint32_t nxboot_main(void) {
     print(SCREEN_LOG_LEVEL_INFO, u8"[NXBOOT] Configured Stratosphere...\n");
 
     /* Patch package2, adding Thermosphère + custom KIPs. */
-    package2_rebuild_and_copy(package2, MAILBOX_EXOSPHERE_CONFIGURATION->target_firmware, emummc, emummc_size);
+    package2_rebuild_and_copy(package2, MAILBOX_EXOSPHERE_CONFIGURATION->target_firmware, mesosphere, mesosphere_size, emummc, emummc_size);
 
     /* Set detected FS version. */
     MAILBOX_EXOSPHERE_CONFIGURATION->emummc_cfg.base_cfg.fs_version = stratosphere_get_fs_version();
diff --git a/fusee/fusee-secondary/src/package2.c b/fusee/fusee-secondary/src/package2.c
index 5987dd0f1..00417b720 100644
--- a/fusee/fusee-secondary/src/package2.c
+++ b/fusee/fusee-secondary/src/package2.c
@@ -44,7 +44,7 @@ static inline size_t align_to_4(size_t s) {
     return ((s + 3) >> 2) << 2;
 }
 
-void package2_rebuild_and_copy(package2_header_t *package2, uint32_t target_firmware, void *emummc, size_t emummc_size) {
+void package2_rebuild_and_copy(package2_header_t *package2, uint32_t target_firmware, void *mesosphere, size_t mesosphere_size, void *emummc, size_t emummc_size) {
     package2_header_t *rebuilt_package2;
     size_t rebuilt_package2_size;
     void *kernel;
@@ -95,6 +95,17 @@ void package2_rebuild_and_copy(package2_header_t *package2, uint32_t target_firm
         fatal_error("Error: inappropriate kernel embedded ini context");
     }
 
+    /* Use mesosphere instead of Nintendo's kernel when present. */
+    if (mesosphere != NULL && mesosphere_size != 0) {
+        kernel = mesosphere;
+        kernel_size = mesosphere_size;
+
+        /* Patch mesosphere to use our rebuilt ini. */
+        *(volatile uint64_t *)((uintptr_t)mesosphere + 8) = (uint64_t)mesosphere_size;
+
+        print(SCREEN_LOG_LEVEL_DEBUG, "Using Mesosphere...\n");
+    }
+
     print(SCREEN_LOG_LEVEL_DEBUG, "Rebuilding the INI1 section...\n");
     if (target_firmware < ATMOSPHERE_TARGET_FIRMWARE_8_0_0) {
         package2_get_src_section((void *)&orig_ini1, package2, PACKAGE2_SECTION_INI1);
diff --git a/fusee/fusee-secondary/src/package2.h b/fusee/fusee-secondary/src/package2.h
index e2f89f3a4..d77eb2094 100644
--- a/fusee/fusee-secondary/src/package2.h
+++ b/fusee/fusee-secondary/src/package2.h
@@ -94,6 +94,6 @@ static inline uint8_t package2_meta_get_header_version(const package2_meta_t *me
     return (uint8_t)((metadata->ctr_dwords[1] ^ (metadata->ctr_dwords[1] >> 16) ^ (metadata->ctr_dwords[1] >> 24)) & 0xFF);
 }
 
-void package2_rebuild_and_copy(package2_header_t *package2, uint32_t target_firmware, void *emummc, size_t emummc_size);
+void package2_rebuild_and_copy(package2_header_t *package2, uint32_t target_firmware, void *mesosphere, size_t mesosphere_size, void *emummc, size_t emummc_size);
 
 #endif