diff --git a/exosphere/Makefile b/exosphere/Makefile
index 7c638dfab..3b9792116 100644
--- a/exosphere/Makefile
+++ b/exosphere/Makefile
@@ -37,7 +37,7 @@ ARCH	:=	-march=armv8-a -mtune=cortex-a57 -mgeneral-regs-only #<- important
 DEFINES	:=	-D__CCPLEX__ -DATMOSPHERE_GIT_BRANCH=\"$(AMSBRANCH)\" -DATMOSPHERE_GIT_REV=\"$(AMSREV)\" -DATMOSPHERE_RELEASE_VERSION_HASH="0x$(AMSHASH)"
 CFLAGS	:= \
 	-g \
-	-O2 \
+	-Os \
 	-ffunction-sections \
 	-fdata-sections \
 	-fomit-frame-pointer \
diff --git a/exosphere/lp0fw/Makefile b/exosphere/lp0fw/Makefile
index e8afccfd1..b3b032b84 100644
--- a/exosphere/lp0fw/Makefile
+++ b/exosphere/lp0fw/Makefile
@@ -29,7 +29,7 @@ ARCH	:=	-march=armv4t -mtune=arm7tdmi -mthumb -mthumb-interwork
 
 CFLAGS	:= \
 		-g \
-		-O2 \
+		-Os \
 		-ffunction-sections \
 		-fdata-sections \
 		-fomit-frame-pointer \
diff --git a/exosphere/rebootstub/Makefile b/exosphere/rebootstub/Makefile
index 0eadd1314..ff265beef 100644
--- a/exosphere/rebootstub/Makefile
+++ b/exosphere/rebootstub/Makefile
@@ -29,7 +29,7 @@ ARCH	:=	-march=armv4t -mtune=arm7tdmi -mthumb -mthumb-interwork
 
 CFLAGS	:= \
 		-g \
-		-O2 \
+		-Os \
 		-ffunction-sections \
 		-fdata-sections \
 		-fomit-frame-pointer \
diff --git a/exosphere/sc7fw/Makefile b/exosphere/sc7fw/Makefile
index 0eadd1314..ff265beef 100644
--- a/exosphere/sc7fw/Makefile
+++ b/exosphere/sc7fw/Makefile
@@ -29,7 +29,7 @@ ARCH	:=	-march=armv4t -mtune=arm7tdmi -mthumb -mthumb-interwork
 
 CFLAGS	:= \
 		-g \
-		-O2 \
+		-Os \
 		-ffunction-sections \
 		-fdata-sections \
 		-fomit-frame-pointer \
diff --git a/exosphere/src/configitem.c b/exosphere/src/configitem.c
index 4adb878b3..b53421d6f 100644
--- a/exosphere/src/configitem.c
+++ b/exosphere/src/configitem.c
@@ -284,10 +284,6 @@ uint32_t configitem_get(bool privileged, ConfigItem item, uint64_t *p_outvalue)
             /* UNOFFICIAL: Gets whether this unit has the RCM bug patched. */
             *p_outvalue = (int)(fuse_has_rcm_bug_patch());;
             break;
-        case CONFIGITEM_EMUNAND_CONFIG:
-            /* UNOFFICIAL: Gets configuration meta for emunand. */
-            *p_outvalue = 1; //exosphere_get_emunand_config();
-            break;
         default:
             result = 2;
             break;
diff --git a/exosphere/src/configitem.h b/exosphere/src/configitem.h
index f727e87f0..b9600c833 100644
--- a/exosphere/src/configitem.h
+++ b/exosphere/src/configitem.h
@@ -45,9 +45,6 @@ typedef enum {
     CONFIGITEM_NEEDS_SHUTDOWN = 65002,
     CONFIGITEM_EXOSPHERE_VERHASH = 65003,
     CONFIGITEM_HAS_RCM_BUG_PATCH = 65004,
-
-    /* These are unofficial, emunand-related. */
-    CONFIGITEM_EMUNAND_CONFIG = 65100,
 } ConfigItem;
 
 #define REBOOT_KIND_NO_REBOOT     0
diff --git a/exosphere/src/emummc_cfg.h b/exosphere/src/emummc_cfg.h
new file mode 100644
index 000000000..3a7f01f5b
--- /dev/null
+++ b/exosphere/src/emummc_cfg.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+ 
+#ifndef EXOSPHERE_EMUMMC_CONFIG_H
+#define EXOSPHERE_EMUMMC_CONFIG_H
+
+#include <stdint.h>
+#include <atmosphere.h>
+#include "utils.h"
+
+/* "EFS0" */
+#define MAGIC_EMUMMC_CONFIG (0x30534645)
+
+#define EMUMMC_FILE_PATH_MAX (0x80)
+
+typedef enum {
+   EMUMMC_TYPE_NONE = 0,
+   EMUMMC_TYPE_PARTITION = 1,
+   EMUMMC_TYPE_FILES = 2,
+} emummc_type_t;
+
+typedef enum {
+    EMUMMC_MMC_NAND = 0,
+    EMUMMC_MMC_SD = 1,
+    EMUMMC_MMC_GC = 2,
+} emummc_mmc_t;
+
+typedef struct {
+    uint32_t magic;
+    uint32_t type;
+    uint32_t id;
+    uint32_t fs_version;
+} emummc_base_config_t;
+
+typedef struct {
+    uint64_t start_sector;
+} emummc_partition_config_t;
+
+typedef struct {
+    char path[EMUMMC_FILE_PATH_MAX];
+} emummc_file_config_t;
+
+typedef struct {
+    emummc_base_config_t base_cfg;
+    union {
+        emummc_partition_config_t partition_cfg;
+        emummc_file_config_t file_cfg;
+    };
+} exo_emummc_config_t;
+
+_Static_assert(sizeof(exo_emummc_config_t) == 0x90, "exo_emummc_config_t definition!");
+
+#endif
diff --git a/exosphere/src/exocfg.c b/exosphere/src/exocfg.c
index ad782b33d..7cf9488bd 100644
--- a/exosphere/src/exocfg.c
+++ b/exosphere/src/exocfg.c
@@ -84,10 +84,10 @@ unsigned int exosphere_should_disable_usermode_exception_handlers(void) {
     return EXOSPHERE_CHECK_FLAG(EXOSPHERE_FLAG_DISABLE_USERMODE_EXCEPTION_HANDLERS);
 }
 
-uint64_t exosphere_get_emunand_config(void) {
+const exo_emummc_config_t *exosphere_get_emummc_config(void) {
     if (!g_has_loaded_config) {
         generic_panic();
     }
 
-    return g_exosphere_cfg.emunand_config;
+    return &g_exosphere_cfg.emummc_cfg;
 }
diff --git a/exosphere/src/exocfg.h b/exosphere/src/exocfg.h
index d6a12eb22..316aa5646 100644
--- a/exosphere/src/exocfg.h
+++ b/exosphere/src/exocfg.h
@@ -22,6 +22,7 @@
 #include "utils.h"
 
 #include "memory_map.h"
+#include "emummc_cfg.h"
 
 /* This serves to set configuration for *exosphere itself*, separate from the SecMon Exosphere mimics. */
 
@@ -45,11 +46,11 @@ typedef struct {
     uint32_t magic;
     uint32_t target_firmware;
     uint32_t flags;
-    uint32_t reserved;
-    uint64_t emunand_config;
+    uint32_t reserved[5];
+    exo_emummc_config_t emummc_cfg;
 } exosphere_config_t;
 
-_Static_assert(sizeof(exosphere_config_t) == 0x18, "exosphere config definition");
+_Static_assert(sizeof(exosphere_config_t) == 0x20 + sizeof(exo_emummc_config_t), "exosphere config definition");
 
 unsigned int exosphere_load_config(void);
 unsigned int exosphere_get_target_firmware(void);
@@ -58,7 +59,7 @@ unsigned int exosphere_should_override_debugmode_priv(void);
 unsigned int exosphere_should_override_debugmode_user(void);
 unsigned int exosphere_should_disable_usermode_exception_handlers(void);
 
-uint64_t exosphere_get_emunand_config(void);
+const exo_emummc_config_t *exosphere_get_emummc_config(void);
 
 static inline unsigned int exosphere_get_target_firmware_for_init(void) {
     const unsigned int magic = MAILBOX_EXOSPHERE_CONFIG_PHYS.magic;
diff --git a/exosphere/src/my_libc.c b/exosphere/src/my_libc.c
index 35bd35bbb..2117f2483 100644
--- a/exosphere/src/my_libc.c
+++ b/exosphere/src/my_libc.c
@@ -819,7 +819,7 @@ strcpy (char *dst0,
 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
   char *s = dst0;
 
-  while (*dst0++ = *src0++)
+  while ((*dst0++ = *src0++))
     ;
 
   return s;
diff --git a/exosphere/src/smc_ams.c b/exosphere/src/smc_ams.c
index f71d947a6..3fc1769ee 100644
--- a/exosphere/src/smc_ams.c
+++ b/exosphere/src/smc_ams.c
@@ -13,8 +13,8 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
- 
- 
+
+
 #include <stdatomic.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -26,6 +26,8 @@
 #include "synchronization.h"
 #include "memory_map.h"
 #include "mmu.h"
+#include "userpage.h"
+#include "exocfg.h"
 
 static atomic_flag g_ams_userpage_mapped = ATOMIC_FLAG_INIT;
 static atomic_flag g_ams_iram_page_mapped = ATOMIC_FLAG_INIT;
@@ -94,42 +96,42 @@ uint32_t ams_iram_copy(smc_args_t *args) {
     /* args->X[2] = IRAM address, must be 4-byte aligned. */
     /* args->X[3] = size (must be <= 0x1000 and 4-byte aligned). */
     /* args->X[4] = 0 for read, 1 for write. */
-    
+
     const uintptr_t dram_address = (uintptr_t)args->X[1];
     const uintptr_t iram_address = (uintptr_t)args->X[2];
     const uintptr_t dram_page_offset = (dram_address & 0xFFFULL);
     const uintptr_t iram_page_offset = (iram_address & 0xFFFULL);
     const size_t size = args->X[3];
     const uint32_t option = (uint32_t)args->X[4];
-            
+
     /* Validate addresses. */
     if (!ams_is_user_addr_valid(dram_address) || !ams_is_iram_addr_valid(iram_address)) {
         return 2;
     }
-    
+
     /* Validate size. */
     if (size > 0x1000 || (size + dram_page_offset) > 0x1000 || (size + iram_page_offset) > 0x1000) {
         return 2;
     }
-    
+
     /* Validate alignment. */
     if (size % sizeof(uint32_t) || dram_page_offset % sizeof(uint32_t) || iram_page_offset % sizeof(uint32_t)) {
         return 2;
     }
-    
+
     /* Validate argument. */
     if (option != 0 && option != 1) {
         return 2;
     }
-    
+
     /* Map pages. */
     ams_map_userpage(dram_address);
     ams_map_irampage(iram_address);
-    
+
     /* Set source/destination for copy. */
     volatile uint32_t *dram_ptr = (volatile uint32_t *)(AMS_USER_PAGE_SECURE_MONITOR_ADDR + dram_page_offset);
     volatile uint32_t *iram_ptr = (volatile uint32_t *)(AMS_IRAM_PAGE_SECURE_MONITOR_ADDR + iram_page_offset);
-    
+
     volatile uint32_t *dst;
     volatile uint32_t *src;
     const size_t num_dwords = size / sizeof(uint32_t);
@@ -140,19 +142,19 @@ uint32_t ams_iram_copy(smc_args_t *args) {
         dst = iram_ptr;
         src = dram_ptr;
     }
-    
+
     /* Actually copy data. */
     for (size_t i = 0; i < num_dwords; i++) {
         dst[i] = src[i];
     }
-    
+
     /* Flush! */
-    flush_dcache_range((void *)dst, (void *)(dst + num_dwords));    
-    
+    flush_dcache_range((void *)dst, (void *)(dst + num_dwords));
+
     /* Unmap pages. */
     ams_unmap_irampage();
     ams_unmap_userpage();
-    
+
     return 0;
 }
 
@@ -222,3 +224,50 @@ uint32_t ams_write_address(smc_args_t *args) {
 
     return 0;
 }
+
+uint32_t ams_get_emummc_config(smc_args_t *args) {
+    /* This retrieves configuration for the current emummc context. */
+    /* args->X[1] = MMC id, must be size-bytes aligned and readable by EL0. */
+    /* args->X[2] = Pointer to output (for path for filebased), must be at least 0x80 bytes. */
+    upage_ref_t page_ref;
+    const uint32_t mmc_id = (uint32_t)args->X[1];
+    void *user_address = (void *)args->X[2];
+    const exo_emummc_config_t *emummc_cfg = exosphere_get_emummc_config();
+
+    if (mmc_id != EMUMMC_MMC_NAND) {
+        /* Emummc config for non-NAND storage is not yet implemented. */
+        return 1;
+    }
+
+    if (emummc_cfg->base_cfg.type == EMUMMC_TYPE_NONE) {
+        /* Just copy base config. */
+        memset(args, 0, sizeof(*args));
+        memcpy(&args->X[1], emummc_cfg, sizeof(emummc_cfg->base_cfg));
+        _Static_assert(sizeof(emummc_cfg->base_cfg) <= sizeof(*args) - sizeof(args->X[0]), "Emunand base config too big!");
+        return 0;
+    } else if (emummc_cfg->base_cfg.type == EMUMMC_TYPE_PARTITION) {
+        /* Copy base config and partition config. */
+        memset(args, 0, sizeof(*args));
+        memcpy(&args->X[1], emummc_cfg, sizeof(emummc_cfg->base_cfg) + sizeof(emummc_cfg->partition_cfg));
+        _Static_assert(sizeof(emummc_cfg->base_cfg) + sizeof(emummc_cfg->partition_cfg) <= sizeof(*args) - sizeof(args->X[0]), "Emunand partition config too big!");
+        return 0;
+    } else if (emummc_cfg->base_cfg.type == EMUMMC_TYPE_FILES) {
+        /* Copy path to userpage. */
+        /* Initialize page reference. */
+        if (upage_init(&page_ref, user_address) == 0) {
+            return 2;
+        }
+        /* Copy result output back to user. */
+        if (secure_copy_to_user(&page_ref, user_address, &emummc_cfg->file_cfg, sizeof(emummc_cfg->file_cfg)) == 0) {
+            return 2;
+        }
+
+        /* Copy base config afterwards, since this can't fail. */
+        memset(args, 0, sizeof(*args));
+        memcpy(&args->X[1], emummc_cfg, sizeof(emummc_cfg->base_cfg));
+        _Static_assert(sizeof(emummc_cfg->base_cfg) <= sizeof(*args) - sizeof(args->X[0]), "Emunand base config too big!");
+        return 0;
+    } else {
+        return 2;
+    }
+}
\ No newline at end of file
diff --git a/exosphere/src/smc_ams.h b/exosphere/src/smc_ams.h
index cbae64d63..4061dd454 100644
--- a/exosphere/src/smc_ams.h
+++ b/exosphere/src/smc_ams.h
@@ -22,6 +22,8 @@
 uint32_t ams_iram_copy(smc_args_t *args);
 uint32_t ams_write_address(smc_args_t *args);
 
+uint32_t ams_get_emummc_config(smc_args_t *args);
+
 void ams_map_irampage(uintptr_t iram_address);
 void ams_unmap_irampage(void);
 
diff --git a/exosphere/src/smc_api.c b/exosphere/src/smc_api.c
index 65762233e..5a5d6cadc 100644
--- a/exosphere/src/smc_api.c
+++ b/exosphere/src/smc_api.c
@@ -78,6 +78,7 @@ uint32_t smc_read_write_register(smc_args_t *args);
 /* Atmosphere SMC prototypes */
 uint32_t smc_ams_iram_copy(smc_args_t *args);
 uint32_t smc_ams_write_address(smc_args_t *args);
+uint32_t smc_ams_get_emummc_config(smc_args_t *args);
 
 /* TODO: Provide a way to set this. It's 0 on non-recovery boot anyway... */
 static uint32_t g_smc_blacklist_mask = 0;
@@ -135,6 +136,7 @@ static smc_table_entry_t g_smc_ams_table[] = {
     {0xF0000201, 0, smc_ams_iram_copy},
     {0xF0000002, 0, smc_read_write_register},
     {0xF0000003, 0, smc_ams_write_address},
+    {0xF0000404, 0, smc_ams_get_emummc_config},
 };
 #define SMC_AMS_HANDLERS (sizeof(g_smc_ams_table) / sizeof(g_smc_ams_table[0]))
 
@@ -724,3 +726,7 @@ uint32_t smc_ams_iram_copy(smc_args_t *args) {
 uint32_t smc_ams_write_address(smc_args_t *args) {
     return smc_wrapper_sync(args, ams_write_address);
 }
+
+uint32_t smc_ams_get_emummc_config(smc_args_t *args) {
+    return smc_wrapper_sync(args, ams_get_emummc_config);
+}
diff --git a/exosphere/src/userpage.c b/exosphere/src/userpage.c
index 3be1d5335..51cdf48b0 100644
--- a/exosphere/src/userpage.c
+++ b/exosphere/src/userpage.c
@@ -23,7 +23,7 @@
 
 static uintptr_t g_user_page_user_address = 0ull;
 
-static inline uintptr_t get_page_for_address(void *address) {
+static inline uintptr_t get_page_for_address(const void *address) {
     return ((uintptr_t)(address)) & ~0xFFFULL;
 }
 
@@ -56,7 +56,7 @@ bool upage_init(upage_ref_t *upage, void *user_address) {
     return upage->secure_monitor_address != 0ull;
 }
 
-bool user_copy_to_secure(upage_ref_t *upage, void *secure_dst, void *user_src, size_t size) {
+bool user_copy_to_secure(upage_ref_t *upage, void *secure_dst, const void *user_src, size_t size) {
     /* Fail if the page doesn't match. */
     if (get_page_for_address(user_src) != upage->user_address) {
         return false;
@@ -67,14 +67,14 @@ bool user_copy_to_secure(upage_ref_t *upage, void *secure_dst, void *user_src, s
         return false;
     }
 
-    void *secure_src = (void *)(upage->secure_monitor_address + ((uintptr_t)user_src - upage->user_address));
+    const void *secure_src = (const void *)(upage->secure_monitor_address + ((uintptr_t)user_src - upage->user_address));
     if (size != 0) {
         memcpy(secure_dst, secure_src, size);
     }
     return true;
 }
 
-bool secure_copy_to_user(upage_ref_t *upage, void *user_dst, void *secure_src, size_t size) {
+bool secure_copy_to_user(upage_ref_t *upage, void *user_dst, const void *secure_src, size_t size) {
     /* Fail if the page doesn't match. */
     if (get_page_for_address(user_dst) != upage->user_address) {
         return false;
diff --git a/exosphere/src/userpage.h b/exosphere/src/userpage.h
index 19c140b20..23742db1c 100644
--- a/exosphere/src/userpage.h
+++ b/exosphere/src/userpage.h
@@ -33,7 +33,7 @@ typedef struct {
 
 bool upage_init(upage_ref_t *user_page, void *user_address);
 
-bool user_copy_to_secure(upage_ref_t *user_page, void *secure_dst, void *user_src, size_t size);
-bool secure_copy_to_user(upage_ref_t *user_page, void *user_dst, void *secure_src, size_t size);
+bool user_copy_to_secure(upage_ref_t *user_page, void *secure_dst, const void *user_src, size_t size);
+bool secure_copy_to_user(upage_ref_t *user_page, void *user_dst, const void *secure_src, size_t size);
 
 #endif