I'm trying, with the help from Ian Molton, to install Linux on my Toshiba e800 PDA.
This is where CE 2k3 stops, the calibration step:
Useless to say that my device is unusable in the state. I had to do something about it. There was one and only one option in my opinion: run Linux, of course!
Lots of information was gathered from: Linux on the Toshiba e-series PDAs and sub-pages, most notably the "debricking" page.
I've had a 9-pin ribon cable soldered on the PCB (by a colleague of mine, I tend to be clumsy with small things):
Left of the picture is the top of the PDA. The JTAG connector is on the PCB, right in front of you, covered by a solid thick plastic band.
Here's the pinout for the JTAG pads, when looking at the PDA as in the picture above:
|Signal|| || || || || || ||
Again, Ian has done most of the needed job to drive this adpater from software. See there for how to get the software.
Here is a typical
bsrflash session that dumps the first Mebibyte from the flash:
# bsrflash r dump.bin 1048576 Probing available busses... Intel PXA255 A0 c8026496 Probing for devices... Found Intel K3 strataflash in 2x16 bit mode. Reading data: 000eb154 / 000ffffc
On my computer (x86_64 at 2.2GHz), reading 1MiB takes 30min. Yes, you read correctly: thirty minutes! This is roughly 583 byte per second. So, 32Mib take 16 hours!
If you get something like the following:
# ./bsrflash r dump.bin 1048576 Probing available busses... Intel PXA255 A0 c8026496 Probing for devices... No devices found.
then you are not fast enough. After the PDA has been powered on (using the hard reset slidder, at the bottom), you have a window of about 1 second to run
bsrflash, or the WinCE loader will kind of rellocate the flash so that it is no longer available at
0x0 (we still have to figure how it does that, and how to work around this feature).
When dumping the flash, Ian suggests that you dump it a second time and
cmp(1) the two files to check for transfers glitches (JTAG has no CRC or whatsoever). If they differ, then:
bsrflashmore robust; apply them all in order:
If you applied the patch set above, then usage of
bsrflash changes when reading the flash:
bsrflash r <filename> <size> [samples]
samples is the number of identical and consecutive samples of a single address that are required to validate that the data at this address was read successfully. 2 is most probably enough, 3 is my choice, while 4 and above may be overkill (but acceptable if you dump a small size). Setting this to 2 will double the download time; setting to 3 will triple it; and so on… Defaults to 1.
Here is an example of the new usage:
# bsrflash r dump.bin 1048576 3 Probing available busses... Intel PXA255 A0 c8026496 Probing for devices... Found Intel K3 strataflash in 2x16 bit mode. Reading data: 00000fb8 / 000ffffc : read error, retrying Reading data: 0001d870 / 000ffffc : read error, retrying Reading data: 000eb154 / 000ffffc
UPDATE 20080131 Ian has commited the 4 changes above into his GIT tree.
<box round red 640px|WARNING>
Do NOT try to use the bootloader without prior confirmed JTAG access!
If you use it on your device and it breaks, don't come moaning and whining, neither Ian nor I will be held responsible for the breakage.
Once you decide to replace the original bootloader by APEX, you're on your own.
You've been warned. </box>
We are using APEX as bootloader as an initial attempt at having a fully open source bootloader. We may end up porting a more common bootloader (namely, U-Boot) once we master the boot sequence and hardware initialisation.
For now the APEX port to the e800 is very alpha. Here is a table of the status of some important items, somewhat in order of importance:
|JTAG PUTC||Missing, code is known|
|SDRAM||Timings are known, register values are there, but init sequence is missing|
|Full serial console||Missing|
|Flash driver||Missing, should be pretty obvious: CFI is already suported in APEX|
|Environment||Missing, nothing machine-specific though|
|Zmodem download||Missing, nothing machine-specific though|
|Button access||Missing, should be quite easy|
|Boot menu||Select between different kernels. Missing, highly wanted, needs button access. There is code to draw characters (thx Ian!)|
|Splash Logo||Nice APEX logo in background, progress bar, and all the fuzz. Missing, highly wanted, most important!|
|SD and CF||Boot from off-board SD and CF. Missing, complex, but would be nice|
|IrDA console||Console on the left-hand side IrDA port. Missing|
|WinCE support||Boot WinCE from APEX. Missing, will most probably never ever happen|
For the adventurous, the port is on-going in the
ymorin_e800 branch in Ian's GIT cloned tree. I'm pushing there whenever I have some interesting stuff done.
We'll eventually push back to the original APEX GIT tree once we are stable enough.