From 5347c41ac6ae948106bcdf94dc47e8c44e60a318 Mon Sep 17 00:00:00 2001 From: Velsoth Date: Sat, 1 Sep 2018 22:01:09 +0100 Subject: [PATCH] README: primordial documentation on booting from the external microSD card --- README.md | 44 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 43 insertions(+), 1 deletion(-) diff --git a/README.md b/README.md index 29d4f03..a4c0cf5 100644 --- a/README.md +++ b/README.md @@ -136,7 +136,49 @@ sync Booting from the external microSD card -------------------------------------- -TODO + +* Insert the external microSD card in the ereader and boot it up. + +* Get a shell on the device, either via Telnet, SSH or some sort of terminal emulator. + +* On the ereader shell, mount the rootfs as read only and clone the internal memory into the external microSD card: + +``` +umount /mnt/onboard +mount -o remount,ro / +dd if=/dev/mmcblk0 of=/dev/mmcblk1 +``` + +* Remount the filesystems with their default options: + +``` +mount -o remount,rw / +mount -t vfat -o noatime,nodiratime,shortname=mixed,utf8 /dev/mmcblk0p3 /mnt/onboard +``` + +* Remove the microSD card from the ereader and insert it into a computer with a microSD card reader. + +* Extract the hardware configuration block from the microSD card. For example, on a GNU/Linux computer, assuming the SD card is at /dev/mmcblk0 (replace as needed): + +``` +dd bs=512 skip=1024 count=1 if=/dev/mmcblk0 of=ereader.hwconfig +``` + +* Use a hex editor to change the byte at offset 0x3F (63) from 0 to 1: + +``` +printf '\x01' | dd of=ereader.hwconfig bs=1 seek=63 count=1 conv=notrunc +``` + +* Write it back to the microSD card + +``` +dd if=ereader.hwconfig bs=512 seek=1024 of=/dev/mmcblk0 +``` + +* Proceed with the installation as documented in **Installation on the internal microSD**. + +* Hold down the power and backlight buttons while booting until the LED is blinking to boot from the external microSD card. Notes for developers