This article is part of an extended series on Kobo development and investigation
Apparently I have to make this more obvious:
- Take a backup of your Kobo's SD card before doing anything. If something doesn't work, you can't fix your Kobo without this backup. I will not send you a backup.
- Any device hacking is risky. If you can't afford to break your device, leave now.
The Kobo's boot splash image is stored in unpartitioned space on the internal MicroSD flash. It's an 600x800 4-bit greyscale Windows bitmap (not RLE compressed) starting 1026 512-byte sectors from the beginning of /dev/mmcblk0 (the onboard SD).
Before trying to modify the boot splash image or anything else on the onboard SD card, make a backup of your Kobo's firmware by disk-imaging the internal SD card. If you don't back it up and you damage the kernel or bootloader you won't even be able to factory reset your device; it'll be useless.
If you use a bitmap that is too large you will render your kobo useless, so be careful. I've verified a bitmap of 240120 bytes, saved from Adobe Photoshop CS2, to work on my Kobo Wifi.
`file logo.bmp' should report
PC bitmap, Windows 3.x format, 600 x 800 x 4
I haven't found any unix/linux based tools that will write 4-bit greyscale Windows Bitmap images yet, so Photoshop is your best bet. Recommendations appreciated.
The boot splash image may be replaced by putting a compatible bitmap on the user-accessible onboard fat32 partition. It must be located at
.kobo/upgrade/logo.bmp. Once placed, disconnect the kobo. It'll detect the upgrade files automatically, apply them, and reboot. On reboot, it'll show the new splash.
(Sorry for the horrible phone-camera pic)