Hello, u-boot-users,
Below is the copy of my message posted yesterday to arm-linux mailing list. I didn't get a reply yet but I believe this list is better choice :)
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Recently I bought ebook reading device called REB1100 (www.rca.com). It is built on ARM720T microprocessor, has 64Kb of Atmel 27LV512 EPROM with romfs (bios), 8Mb of NAND flash, Cirrus Logic EP7212 chip with LCD controller and audio. Also it has modem, SMC interface, IR interface and... cool rubber surface :)
Now the question. Is it somehow possible to install [arm/uc]linux there? I study related materials on armlinx website, on uclinux.org, ucdot and some others but yet can't realize from what to start.
Here are results of my "investigations".
First, this CPU has MMU so I can't decide what do I need: uClinux or ARM linux :) [What was confused me - uClinux is for non-MMU machines, but there are patches for ARM7DMI CPU]
When REB1100 starts it executes code from EPROM. The program there implementing simple filesystem, has USB driver and some logic which allow it to install and run 'firmware' (OS, Reader): it is possible to do all this in special DEBUG mode with a tool called "rebhack". Lets call it BIOS.
The firmware is on NAND Flash. As I understand, BIOS do some checks and then runs [or not runs if checks are failed] the OS.
Firmware has extension .rff and is compressed. It has 512 bytes header which contains some control and descriptive fields, among them there is Execution Address. It points to exactly 1Mb.
I hope it is possible to install Linux onto NAND Flash without changing EPROM. I believe, to do that, it is enough to make special .rff which contains boot loader.
I have images of OS and BIOS but can't find disassembler for ARM7 CPU (can you recommend one? Is there a modification of objdump for ARM?)
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An hour ago I've got the sources of U-Boot and read README file on top level. From there I realized two things: 1) To get U-Boot image I have to start a new board. 2) U-Boot is installed into ROM, so I'll need to re-burn EPROM. It is not really a problem for me, but as I said above, I would be happy not to touch it and do all the stff in NAND Samsung Flash.
I look forward to your answers. Thanks.