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Rockbox mail archiveSubject: Re: Rockbox won't start from flash, any ideas?Re: Rockbox won't start from flash, any ideas?
From: Rune Wiinberg <colourless_at_stud.ku.dk>
Date: Wed, 25 Jun 2003 15:15:42 +0200 Hi Jörg. Did you try to reverse engineer a dump of the original flash content? Wouldn't this enable you to figure out the necessary initialization code? Just a thought :-) / Rune ----- Original Message ----- From: <idc-dragon_at_gmx.de> To: <rockbox_at_cool.haxx.se> Sent: Wednesday, June 25, 2003 2:21 PM Subject: Rockbox won't start from flash, any ideas? > Hello, > > frequent readers of this may know that I'm working on getting to Rockbox > start from flash memory, kicking out the original firmware. The reward will be a > much faster "On"-to-music time. Irony has it that I have one of the few > boxes with the wrong flash chip, not in-system programmable. But a new one is on > order, I'm desperately waiting for it. > > Meanwhile I have built my toolchain for UART boot (requires the serial mod). > With a little extra hardware mod (pulling the LCD lines low instead of high) > I can exploit a mode where the boot ROM expects code from the UART. A PC > application now transfers a little monitor program to the internal RAM. When > that's done the two can talk, the current command set allows memory read/write > and jumping to an address. > > This is sufficient to program the flash (even if completely garbled, because > UART boot comes before flash boot) and other tricks. Currently I'm > "practicing" to start Rockbox. To do that, I use the monitor to configure the DRAM > controller in the same way the flash boot does. When I have the DRAM available, > I load the rockbox binary into place and jump to it. > > Expectedly, this didn't really work. The big difference is that I "cold > start" rockbox, with no firmware running ahead of it. In the normal case, Rockbox > is loaded into an environment where "the bed is already made", the firmware > has already initialized much of the hardware. > > All it currently does is switching on the backlight for a few seconds, then > shutting it off again. No splashscreen, no harddisk activity. A bit > disappointing. Does this ring a bell to anybody, what initialization might be missing? > > My next plan is to use my toolchain to not load rockbox, but the gdb stub. > That can in turn load a debug version of rockbox and allows to step around > there. However, my past experience with gdb (under Windows) is no good. The > target connection was very unreliable, the debug application was often frozen and > had to be killed. Is anybody debugging the box under Windows? Maybe I can > persuade a Linux guy with gdb to do the UART boot mod? > > So long, > Joerg > > -- > +++ GMX - Mail, Messaging & more http://www.gmx.net +++ > Bitte lächeln! Fotogalerie online mit GMX ohne eigene Homepage! Received on 2003-06-25 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |