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Sailfish/Backup Device

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DISCLAIMER: Be careful with all your actions. The author of this page will not take any responsibility for you if you brick your device. YOU ARE DOING ALL THE FOLLOWING STEPS ON YOUR OWN. Please make sure your device is fully charged


  • fastboot
  • mkbootimg (x64 Linux version in git of jollarecovery)
  • Cross-compile toolchain for armv7hl-hardfloat-linux-gnueabi, if you want to compile your own kernel
  • telnet client
  • Patience
  • MicroSD card with a minimum capacity of 16GB (formatted with a filesystem capable of storing files with 15GB size, e.g. ext4 or btrfs, not FAT32)


Using prebuilt image

  • Download the boot image
  • Start fastboot on your computer (may need to be run as root) (This is not possible with bootloader after update to 1.0.25)
 $ fastboot -i 0x2931 boot boot-telnet-initrd.img
  • While holding the volume down key pressed, connect the USB cable
  • Jolla logo should appear, message "fastboot mode" on the very first line of the display
  • Check if LED turns blue and wait for it to turn red after some time
  • As soon as the LED is red, your network is up and running with the IP and should be running a DHCP server
  • Configure the USB networking on your computer accordingly (if DHCP fails, try "sudo ifconfig usb0 netmask up")
  • Connect to Jolla using telnet
 $ telnet
  • Mount your SD card
 $ mkdir /sd
 $ mount /dev/mmcblk1p1 /sd
  • Backup all your internal eMMC partitons with:
 $ cd /dev
 $ for i in mmcblk0p* ; do echo $i; dd if=$i of=/sd/$i; done; sync
  • Wait a long time until the command finishes
  • Unmount the SD card
 $ umount /sd
  • Reboot normally

Build your own recovery image

Building the kernel

  1. Download sources at:
  2. export ARCH=arm
  3. export CROSS_COMPILE=armv7hl-hardfloat-linux-gnueabi- (replace with your arm crosscompiler)
  4. Make default config: make sbj_defconfig
  5. Change config with make menuconfig (see for example Setting a builtin CONFIG_CMDLINE here is optional as you can set one using mkbootimg.
  6. make -j4 zImage

Building a initramfs

This is a standard Linux concept and there's plenty of documentation around the web and this wiki. You may also use the initramfs in . To create a very simple initramfs, either use a crosscompiler (scratchbox2, crossdev), or just copy the binaries (and libraries!) from the Jolla device. Once you've done that:

  1. In the directory where the initramfs directory is stored, find . | cpio -H newc -o | gzip > ../ramfs.cpio.gz

Packing everything into a boot.img

mkbootimg --cmdline 'root=/dev/ram0 rw init=/init androidboot.hardware=qcom user_debug=31 ehci-hcd.park=3 maxcpus=2' --base 0x00000000 --pagesize 2048 --kernel_offset 0x80208000 --ramdisk_offset 0x82200000 --second_offset 0x81100000 --tags_offset 0x80200100 --board '' --ramdisk ramfs.cpio.gz --kernel kernelsourcetreepath/arch/arm/boot/zImage --output boot.img

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