x1000: Unified flash bootloader installer

Change-Id: Ib1d41d4e7d663ff8a21eb08108c13568f7408533

6 files changed, 390 insertions, 324 deletions

diff --git a/bootloader/x1000.c b/bootloader/x1000.c
index 0b28b7449d..2c61773b11 100644
--- a/bootloader/x1000.c
+++ b/bootloader/x1000.c
@@ -48,16 +48,13 @@
 #include "loader_strerror.h"
 #include "version.h"
 #include "boot-x1000.h"
+#include "installer-x1000.h"
 #include <stddef.h>
 #include <stdbool.h>
 #include <string.h>
 #include <stdio.h>
 #include <stdarg.h>
 
-#ifdef FIIO_M3K
-# include "installer-fiiom3k.h"
-#endif
-
 #if defined(FIIO_M3K)
 # define BL_RECOVERY    BUTTON_VOL_UP
 # define BL_UP          BUTTON_VOL_UP
@@ -68,6 +65,7 @@
 # define BL_DOWN_NAME   "VOL-"
 # define BL_SELECT_NAME "PLAY"
 # define BL_QUIT_NAME   "POWER"
+# define BOOTBACKUP_FILE "/fiiom3k-boot.bin"
 #else
 # error "Missing keymap!"
 #endif
@@ -387,14 +385,12 @@ void reboot(void)
     while(1);
 }
 
-/* TODO: clean this up, make the installer generic as well */
 enum {
     INSTALL,
     BACKUP,
     RESTORE,
 };
 
-#ifdef FIIO_M3K
 void bootloader_action(int which)
 {
     if(init_disk() != 0) {
@@ -414,14 +410,14 @@ void bootloader_action(int which)
 
     int rc;
     switch(which) {
-    case INSTALL: rc = install_boot("/bootloader.m3k");   break;
-    case BACKUP:  rc =  backup_boot("/fiiom3k-boot.bin"); break;
-    case RESTORE: rc = restore_boot("/fiiom3k-boot.bin"); break;
+    case INSTALL: rc = install_bootloader("/bootloader." BOOTFILE_EXT); break;
+    case BACKUP:  rc = backup_bootloader(BOOTBACKUP_FILE); break;
+    case RESTORE: rc = restore_bootloader(BOOTBACKUP_FILE); break;
     default: return;
     }
 
     static char buf[64];
-    snprintf(buf, sizeof(buf), "Failed! Error: %d", rc);
+    snprintf(buf, sizeof(buf), "%s (%d)", installer_strerror(rc), rc);
     const char* msg1 = rc == 0 ? "Success" : buf;
     const char* msg2 = "Press " BL_QUIT_NAME " to continue";
     splash2(0, msg1, msg2);
@@ -429,13 +425,6 @@ void bootloader_action(int which)
     button_clear_queue();
     while(button_get(true) != BL_QUIT);
 }
-#else
-void bootloader_action(int which)
-{
-    (void)which;
-    splash(5*HZ, "Not implemented!");
-}
-#endif
 
 void bootloader_install(void)
 {
diff --git a/firmware/SOURCES b/firmware/SOURCES
index b1024d97da..2414682bb4 100644
--- a/firmware/SOURCES
+++ b/firmware/SOURCES
@@ -1676,9 +1676,12 @@ target/mips/ingenic_x1000/msc-x1000.c
 #if (CONFIG_STORAGE & STORAGE_SD)
 target/mips/ingenic_x1000/sd-x1000.c
 #endif
+#ifdef BOOTLOADER
+target/mips/ingenic_x1000/installer-x1000.c
 target/mips/ingenic_x1000/spl-start.S
 target/mips/ingenic_x1000/spl-x1000.c
 common/ucl_decompress.c
+#endif
 #endif /* CONFIG_CPU == X1000 */
 
 #if defined(ONDA_VX747) || defined(ONDA_VX747P) || defined(ONDA_VX777)
@@ -1711,9 +1714,6 @@ target/mips/ingenic_x1000/fiiom3k/button-fiiom3k.c
 target/mips/ingenic_x1000/fiiom3k/lcd-fiiom3k.c
 target/mips/ingenic_x1000/fiiom3k/power-fiiom3k.c
 target/mips/ingenic_x1000/fiiom3k/spl-fiiom3k.c
-#ifdef BOOTLOADER
-target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.c
-#endif
 #endif /* FIIO_M3K */
 
 #if defined(LYRE_PROTO1)
diff --git a/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.c b/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.c
deleted file mode 100644
index 8ce73bf09e..0000000000
--- a/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.c
+++ /dev/null
@@ -1,253 +0,0 @@
-/***************************************************************************
- *             __________               __   ___.
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
- *                     \/            \/     \/    \/            \/
- * $Id$
- *
- * Copyright (C) 2021 Aidan MacDonald
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-#include "installer-fiiom3k.h"
-#include "nand-x1000.h"
-#include "system.h"
-#include "core_alloc.h"
-#include "file.h"
-#include "microtar.h"
-#include <stdint.h>
-#include <string.h>
-#include <stdio.h>
-
-#define IMAGE_SIZE  (128 * 1024)
-#define TAR_SIZE    (256 * 1024)
-
-static int flash_img_read(uint8_t* buffer)
-{
-    nand_drv* drv = nand_init();
-    nand_lock(drv);
-
-    int rc = nand_open(drv);
-    if(rc < 0)
-        goto error;
-
-    rc = nand_read_bytes(drv, 0, IMAGE_SIZE, buffer);
-    if(rc < 0) {
-        rc = INSTALL_ERR_FLASH(NAND_READ, rc);
-        goto error;
-    }
-
-  error:
-    nand_close(drv);
-    nand_unlock(drv);
-    return rc;
-}
-
-static int flash_img_write(const uint8_t* buffer)
-{
-    nand_drv* drv = nand_init();
-    nand_lock(drv);
-
-    int rc = nand_open(drv);
-    if(rc < 0)
-        goto error;
-
-    rc = nand_write_bytes(drv, 0, IMAGE_SIZE, buffer);
-    if(rc < 0) {
-        rc = INSTALL_ERR_FLASH(NAND_WRITE, rc);
-        goto error;
-    }
-
-  error:
-    nand_close(drv);
-    nand_unlock(drv);
-    return rc;
-}
-
-static int patch_img(mtar_t* tar, uint8_t* buffer, const char* filename,
-                     size_t patch_offset, size_t patch_size)
-{
-    /* Seek to file */
-    mtar_header_t h;
-    int rc = mtar_find(tar, filename, &h);
-    if(rc != MTAR_ESUCCESS) {
-        rc = INSTALL_ERR_MTAR(TAR_FIND, rc);
-        return rc;
-    }
-
-    /* We need a normal file */
-    if(h.type != 0 && h.type != MTAR_TREG)
-        return INSTALL_ERR_BAD_FORMAT;
-
-    /* Check size does not exceed patch area */
-    if(h.size > patch_size)
-        return INSTALL_ERR_BAD_FORMAT;
-
-    /* Read data directly into patch area, fill unused bytes with 0xff */
-    memset(&buffer[patch_offset], 0xff, patch_size);
-    rc = mtar_read_data(tar, &buffer[patch_offset], h.size);
-    if(rc != MTAR_ESUCCESS) {
-        rc = INSTALL_ERR_MTAR(TAR_READ, rc);
-        return rc;
-    }
-
-    return INSTALL_SUCCESS;
-}
-
-int install_boot(const char* srcfile)
-{
-    int rc;
-    mtar_t* tar = NULL;
-    int handle = -1;
-
-    /* Allocate enough memory for image and tar state */
-    size_t bufsize = IMAGE_SIZE + sizeof(mtar_t) + 2*CACHEALIGN_SIZE;
-    handle = core_alloc("boot_image", bufsize);
-    if(handle < 0) {
-        rc = INSTALL_ERR_OUT_OF_MEMORY;
-        goto error;
-    }
-
-    uint8_t* buffer = core_get_data(handle);
-
-    /* Tar state alloc */
-    CACHEALIGN_BUFFER(buffer, bufsize);
-    tar = (mtar_t*)buffer;
-    memset(tar, 0, sizeof(tar));
-
-    /* Image buffer alloc */
-    buffer += sizeof(mtar_t);
-    CACHEALIGN_BUFFER(buffer, bufsize);
-
-    /* Read the flash -- we need an existing image to patch */
-    rc = flash_img_read(buffer);
-    if(rc < 0)
-        goto error;
-
-    /* Open the tarball */
-    rc = mtar_open(tar, srcfile, "r");
-    if(rc != MTAR_ESUCCESS) {
-        rc = INSTALL_ERR_MTAR(TAR_OPEN, rc);
-        goto error;
-    }
-
-    /* Extract the needed files & patch 'em in */
-    rc = patch_img(tar, buffer, "spl.m3k", 0, 12 * 1024);
-    if(rc < 0)
-        goto error;
-
-    rc = patch_img(tar, buffer, "bootloader.ucl", 0x6800, 102 * 1024);
-    if(rc < 0)
-        goto error;
-
-    /* Flash the new image */
-    rc = flash_img_write(buffer);
-    if(rc < 0)
-        goto error;
-
-    rc = INSTALL_SUCCESS;
-
-  error:
-    if(tar && tar->close)
-        mtar_close(tar);
-    if(handle >= 0)
-        core_free(handle);
-    return rc;
-}
-
-int backup_boot(const char* destfile)
-{
-    int rc;
-    int handle = -1;
-    int fd = -1;
-    size_t bufsize = IMAGE_SIZE + CACHEALIGN_SIZE - 1;
-    handle = core_alloc("boot_image", bufsize);
-    if(handle < 0) {
-        rc = INSTALL_ERR_OUT_OF_MEMORY;
-        goto error;
-    }
-
-    uint8_t* buffer = core_get_data(handle);
-    CACHEALIGN_BUFFER(buffer, bufsize);
-
-    rc = flash_img_read(buffer);
-    if(rc < 0)
-        goto error;
-
-    fd = open(destfile, O_CREAT|O_TRUNC|O_WRONLY);
-    if(fd < 0) {
-        rc = INSTALL_ERR_FILE_IO;
-        goto error;
-    }
-
-    ssize_t cnt = write(fd, buffer, IMAGE_SIZE);
-    if(cnt != IMAGE_SIZE) {
-        rc = INSTALL_ERR_FILE_IO;
-        goto error;
-    }
-
-  error:
-    if(fd >= 0)
-        close(fd);
-    if(handle >= 0)
-        core_free(handle);
-    return rc;
-}
-
-int restore_boot(const char* srcfile)
-{
-    int rc;
-    int handle = -1;
-    int fd = -1;
-    size_t bufsize = IMAGE_SIZE + CACHEALIGN_SIZE - 1;
-    handle = core_alloc("boot_image", bufsize);
-    if(handle < 0) {
-        rc = INSTALL_ERR_OUT_OF_MEMORY;
-        goto error;
-    }
-
-    uint8_t* buffer = core_get_data(handle);
-    CACHEALIGN_BUFFER(buffer, bufsize);
-
-    fd = open(srcfile, O_RDONLY);
-    if(fd < 0) {
-        rc = INSTALL_ERR_FILE_NOT_FOUND;
-        goto error;
-    }
-
-    off_t fsize = filesize(fd);
-    if(fsize != IMAGE_SIZE) {
-        rc = INSTALL_ERR_BAD_FORMAT;
-        goto error;
-    }
-
-    ssize_t cnt = read(fd, buffer, IMAGE_SIZE);
-    if(cnt != IMAGE_SIZE) {
-        rc = INSTALL_ERR_FILE_IO;
-        goto error;
-    }
-
-    close(fd);
-    fd = -1;
-
-    rc = flash_img_write(buffer);
-    if(rc < 0)
-        goto error;
-
-  error:
-    if(fd >= 0)
-        close(fd);
-    if(handle >= 0)
-        core_free(handle);
-    return rc;
-}
diff --git a/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.h b/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.h
deleted file mode 100644
index eb700e6689..0000000000
--- a/firmware/target/mips/ingenic_x1000/fiiom3k/installer-fiiom3k.h
+++ /dev/null
@@ -1,51 +0,0 @@
-/***************************************************************************
- *             __________               __   ___.
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
- *                     \/            \/     \/    \/            \/
- * $Id$
- *
- * Copyright (C) 2021 Aidan MacDonald
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
- * KIND, either express or implied.
- *
- ****************************************************************************/
-
-#ifndef __INSTALLER_FIIOM3K_H__
-#define __INSTALLER_FIIOM3K_H__
-
-#include <stddef.h>
-
-#define INSTALL_SUCCESS                 0
-#define INSTALL_ERR_OUT_OF_MEMORY       (-1)
-#define INSTALL_ERR_FILE_NOT_FOUND      (-2)
-#define INSTALL_ERR_FILE_IO             (-3)
-#define INSTALL_ERR_BAD_FORMAT          (-4)
-#define INSTALL_ERR_NAND_OPEN           (-5)
-#define INSTALL_ERR_NAND_IDENTIFY       (-6)
-#define INSTALL_ERR_NAND_READ           (-7)
-#define INSTALL_ERR_NAND_ENABLE_WRITES  (-8)
-#define INSTALL_ERR_NAND_ERASE          (-9)
-#define INSTALL_ERR_NAND_WRITE          (-10)
-#define INSTALL_ERR_TAR_OPEN            (-11)
-#define INSTALL_ERR_TAR_FIND            (-12)
-#define INSTALL_ERR_TAR_READ            (-13)
-#define INSTALL_ERR_MTAR(x,y)           ((INSTALL_ERR_##x)*100 + (y))
-#define INSTALL_ERR_FLASH(x,y)          ((INSTALL_ERR_##x)*100 + (y))
-
-/* Install the Rockbox bootloader from a bootloader.m3k image */
-extern int install_boot(const char* srcfile);
-
-/* Backup or restore the bootloader from a raw NAND image */
-extern int backup_boot(const char* destfile);
-extern int restore_boot(const char* srcfile);
-
-#endif /* __INSTALLER_FIIOM3K_H__ */
diff --git a/firmware/target/mips/ingenic_x1000/installer-x1000.c b/firmware/target/mips/ingenic_x1000/installer-x1000.c
new file mode 100644
index 0000000000..617e6645b7
--- /dev/null
+++ b/firmware/target/mips/ingenic_x1000/installer-x1000.c
@@ -0,0 +1,326 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "installer-x1000.h"
+#include "nand-x1000.h"
+#include "core_alloc.h"
+#include "file.h"
+#include "microtar.h"
+#include <stddef.h>
+
+struct update_part {
+    const char* filename;
+    size_t offset;
+    size_t length;
+};
+
+/* Parts of the flash to update. The offset and length are given in bytes,
+ * offset relative to start of flash. The region's new contents are given
+ * by the named file inside the update archive. If any file is missing, the
+ * update will fail. (gracefully! nothing is written unless the package has
+ * all its components)
+ *
+ * If the update file is smaller than the region size, unused space at the
+ * end of the region is padded with 0xff.
+ *
+ * NOTE: The current code assumes all parts are contiguous. The current
+ * update map fits in one eraseblock, but if it ever needs extending beyond
+ * that, better implement a bitmap to indicate which blocks need updating
+ * and which can be skipped. We don't want to erase and reprogram blocks
+ * for no good reason, it's bad for the flash lifespan.
+ */
+static const struct update_part updates[] = {
+    {
+        .filename = "spl." BOOTFILE_EXT,
+        .offset = 0,
+        .length = 12 * 1024,
+    },
+    {
+        .filename = "bootloader.ucl",
+        .offset = 0x6800,
+        .length = 102 * 1024,
+    },
+};
+
+static const int num_updates = sizeof(updates) / sizeof(struct update_part);
+
+/* calculate the offset and length of the update image; this is constant
+ * for a given target, based on the update parts and the NAND chip geometry.
+ */
+static void get_image_loc(nand_drv* ndrv, size_t* offptr, size_t* lenptr)
+{
+    size_t blk_size = ndrv->chip->page_size << ndrv->chip->log2_ppb;
+    size_t img_off = 0;
+    size_t img_len = 0;
+
+    /* calculate minimal image needed to contain all update blocks */
+    for(int i = 0; i < num_updates; ++i) {
+        img_len = MAX(img_len, updates[i].offset + updates[i].length);
+        img_off = MIN(img_off, updates[i].offset);
+    }
+
+    /* round everything to a multiple of the block size */
+    size_t r_off = blk_size * (img_off / blk_size);
+    size_t r_len = blk_size * ((img_len + img_off - r_off + blk_size - 1) / blk_size);
+
+    *offptr = r_off;
+    *lenptr = r_len;
+}
+
+/* Read in a single part of the update from the tarball, and patch it
+ * into the image */
+static int patch_part(mtar_t* tar, const struct update_part* part,
+                      uint8_t* img_buf, size_t img_off)
+{
+    mtar_header_t h;
+    int rc = mtar_find(tar, part->filename, &h);
+    if(rc != MTAR_ESUCCESS)
+        return IERR_BAD_FORMAT;
+
+    if(h.type != 0 && h.type != MTAR_TREG)
+        return IERR_BAD_FORMAT;
+
+    if(h.size > part->length)
+        return IERR_BAD_FORMAT;
+
+    /* wipe the patched area, and read in the new data */
+    memset(&img_buf[part->offset - img_off], 0xff, part->length);
+    rc = mtar_read_data(tar, &img_buf[part->offset - img_off], h.size);
+    if(rc != MTAR_ESUCCESS)
+        return IERR_FILE_IO;
+
+    return IERR_SUCCESS;
+}
+
+struct updater {
+    int buf_hnd; /* core_alloc handle for our memory buffer */
+    size_t buf_len; /* sizeof the buffer */
+
+    uint8_t* img_buf;
+    size_t img_off; /* image address in flash */
+    size_t img_len; /* image length in flash = size of the buffer */
+
+    mtar_t* tar;
+    nand_drv* ndrv;
+};
+
+static int updater_init(struct updater* u)
+{
+    int rc;
+
+    /* initialize stuff correctly */
+    u->buf_hnd = -1;
+    u->buf_len = 0;
+    u->img_buf = NULL;
+    u->img_off = 0;
+    u->img_len = 0;
+    u->tar = NULL;
+    u->ndrv = NULL;
+
+    /* open NAND */
+    u->ndrv = nand_init();
+    nand_lock(u->ndrv);
+    rc = nand_open(u->ndrv);
+    if(rc != NAND_SUCCESS) {
+        rc = IERR_NAND_OPEN;
+        goto error;
+    }
+
+    get_image_loc(u->ndrv, &u->img_off, &u->img_len);
+
+    /* buf_len is a bit oversized here, but it's not really important */
+    u->buf_len = u->img_len + sizeof(mtar_t) + 2*CACHEALIGN_SIZE;
+    u->buf_hnd = core_alloc("boot_image", u->buf_len);
+    if(u->buf_hnd < 0) {
+        rc = IERR_OUT_OF_MEMORY;
+        goto error;
+    }
+
+    /* allocate from the buffer */
+    uint8_t* buffer = (uint8_t*)core_get_data(u->buf_hnd);
+    size_t buf_len = u->buf_len;
+
+    CACHEALIGN_BUFFER(buffer, buf_len);
+    u->img_buf = buffer;
+    buffer += u->img_len;
+    buf_len -= u->img_len;
+
+    CACHEALIGN_BUFFER(buffer, buf_len);
+    u->tar = (mtar_t*)buffer;
+    memset(u->tar, 0, sizeof(struct mtar_t));
+
+    rc = IERR_SUCCESS;
+
+  error:
+    return rc;
+}
+
+static void updater_cleanup(struct updater* u)
+{
+    if(u->tar && u->tar->close)
+        mtar_close(u->tar);
+
+    if(u->buf_hnd >= 0)
+        core_free(u->buf_hnd);
+
+    if(u->ndrv) {
+        nand_close(u->ndrv);
+        nand_unlock(u->ndrv);
+    }
+}
+
+int install_bootloader(const char* filename)
+{
+    struct updater u;
+    int rc = updater_init(&u);
+    if(rc != IERR_SUCCESS)
+        goto error;
+
+    /* get the image */
+    rc = nand_read_bytes(u.ndrv, u.img_off, u.img_len, u.img_buf);
+    if(rc != NAND_SUCCESS) {
+        rc = IERR_NAND_READ;
+        goto error;
+    }
+
+    /* get the tarball */
+    rc = mtar_open(u.tar, filename, "r");
+    if(rc != MTAR_ESUCCESS) {
+        if(rc == MTAR_EOPENFAIL)
+            rc = IERR_FILE_NOT_FOUND;
+        else if(rc == MTAR_EREADFAIL)
+            rc = IERR_FILE_IO;
+        else
+            rc = IERR_BAD_FORMAT;
+        goto error;
+    }
+
+    /* patch stuff */
+    for(int i = 0; i < num_updates; ++i) {
+        rc = patch_part(u.tar, &updates[i], u.img_buf, u.img_off);
+        if(rc != IERR_SUCCESS)
+            goto error;
+    }
+
+    /* write back the patched image */
+    rc = nand_write_bytes(u.ndrv, u.img_off, u.img_len, u.img_buf);
+    if(rc != NAND_SUCCESS) {
+        rc = IERR_NAND_WRITE;
+        goto error;
+    }
+
+    rc = IERR_SUCCESS;
+
+  error:
+    updater_cleanup(&u);
+    return rc;
+}
+
+int backup_bootloader(const char* filename)
+{
+    int rc, fd = 0;
+    struct updater u;
+
+    rc = updater_init(&u);
+    if(rc != IERR_SUCCESS)
+        goto error;
+
+    /* read image */
+    rc = nand_read_bytes(u.ndrv, u.img_off, u.img_len, u.img_buf);
+    if(rc != NAND_SUCCESS) {
+        rc = IERR_NAND_READ;
+        goto error;
+    }
+
+    /* write to file */
+    fd = open(filename, O_CREAT|O_TRUNC|O_WRONLY);
+    if(fd < 0) {
+        rc = IERR_FILE_IO;
+        goto error;
+    }
+
+    ssize_t cnt = write(fd, u.img_buf, u.img_len);
+    if(cnt < 0 || (size_t)cnt != u.img_len) {
+        rc = IERR_FILE_IO;
+        goto error;
+    }
+
+    rc = IERR_SUCCESS;
+
+  error:
+    if(fd >= 0)
+        close(fd);
+    updater_cleanup(&u);
+    return rc;
+}
+
+int restore_bootloader(const char* filename)
+{
+    int rc, fd = 0;
+    struct updater u;
+
+    rc = updater_init(&u);
+    if(rc != IERR_SUCCESS)
+        goto error;
+
+    /* read from file */
+    fd = open(filename, O_RDONLY);
+    if(fd < 0) {
+        rc = IERR_FILE_NOT_FOUND;
+        goto error;
+    }
+
+    ssize_t cnt = read(fd, u.img_buf, u.img_len);
+    if(cnt < 0 || (size_t)cnt != u.img_len) {
+        rc = IERR_FILE_IO;
+        goto error;
+    }
+
+    /* write image */
+    rc = nand_write_bytes(u.ndrv, u.img_off, u.img_len, u.img_buf);
+    if(rc != NAND_SUCCESS) {
+        rc = IERR_NAND_WRITE;
+        goto error;
+    }
+
+    rc = IERR_SUCCESS;
+
+  error:
+    if(fd >= 0)
+        close(fd);
+    updater_cleanup(&u);
+    return rc;
+}
+
+const char* installer_strerror(int rc)
+{
+    switch(rc) {
+    case IERR_SUCCESS:          return "Success";
+    case IERR_OUT_OF_MEMORY:    return "Out of memory";
+    case IERR_FILE_NOT_FOUND:   return "File not found";
+    case IERR_FILE_IO:          return "Disk I/O error";
+    case IERR_BAD_FORMAT:       return "Bad archive";
+    case IERR_NAND_OPEN:        return "NAND open error";
+    case IERR_NAND_READ:        return "NAND read error";
+    case IERR_NAND_WRITE:       return "NAND write error";
+    default:                    return "Unknown error!?";
+    }
+}
diff --git a/firmware/target/mips/ingenic_x1000/installer-x1000.h b/firmware/target/mips/ingenic_x1000/installer-x1000.h
new file mode 100644
index 0000000000..b71839a907
--- /dev/null
+++ b/firmware/target/mips/ingenic_x1000/installer-x1000.h
@@ -0,0 +1,55 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef __INSTALLER_X1000_H__
+#define __INSTALLER_X1000_H__
+
+/* This API is for the bootloader recovery menu and Rockbox utility to handle
+ * bootloader installation, backup, and restore.
+ *
+ * Currently the installer can only handle NAND flash, although the X1000 can
+ * boot from NOR flash or SD/MMC. Support for other storage media can be added
+ * when there is a target that needs it.
+ *
+ * Bootloader updates are tarballs, and they can "monkey patch" the flash in
+ * a customizable way (but fixed at compile time).
+ *
+ * Backup and restore simply takes the range of eraseblocks touched by the
+ * monkey patch and copies them to or from a regular file.
+ */
+
+enum {
+    IERR_SUCCESS = 0,
+    IERR_OUT_OF_MEMORY,
+    IERR_FILE_NOT_FOUND,
+    IERR_FILE_IO,
+    IERR_BAD_FORMAT,
+    IERR_NAND_OPEN,
+    IERR_NAND_READ,
+    IERR_NAND_WRITE,
+};
+
+extern int install_bootloader(const char* filename);
+extern int backup_bootloader(const char* filename);
+extern int restore_bootloader(const char* filename);
+extern const char* installer_strerror(int rc);
+
+#endif /* __INSTALLER_X1000_H__ */