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Steve Markgraf steve at steve-m.deHi Marcin, On 30.10.2010 13:51, Marcin Mielczarczyk wrote: > In this case, first I'll explain how it works. > Nomenclature: > 1) internal bootloader - bootloader placed at 0x48000000 in System ROM > 2) 2nd stage bootloader or extarnal bootloader - bootloader placed in > NAND - initializes DRAM controller and boots MTK's software - this > bootloader prints info on UART by default > > When MT6235 processor starts it has RM1 bit disabled in EMI_GENA > register (External Memory Interface controller), > which forces ARM926 core to jump first to System ROM (0x48000000). > When internal bootloader is executed it initializes UART to 19200n8 > and checks if specific character is received. Alright, this is how it works on the MT622x as well. > This is source code where you can build your own Download Agent. This > is how I first executed my own code on MT6235. It has all make files > and it's prepared for ADS compiler. > When you'll build your own Download Agent you just select this file in > FlashTool and you have your code executed in RAM. > I saw that you can use it on all MTK platforms. > FlashTool links are also available on pudn.com > I didn't analyze this path of bootloader, but it could be good to have > it if we would like to create our own flashing tool under Linux (i.e. > for flashing U-Boot). That's pretty interesting, since it could be used to create authentificated code for other phones with the secure romloader, too. >> This is great. So far, we have not seen any MT622x based phone that has >> JTAG exposed. Even the Huayu development modules for the MT622x don't have >> it. Well, there is the CECT C3100 which has JTAG solder pads. OpenOCD successfully detected the CPU, but I couldn't halt the ARM core (same problem on the Calypso btw). I tried other random ARM7 targets which had the same EmbeddedICE revision and there it worked. > Yes, I agree. > In this case to download U-Boot to NAND we can use FlashTool (only for Windows). > Then as you stated we can use U-Boot to load code from SD/MMC/serial. Getting osmocon to work with the secure romloader could be an option as well. Currently it only supports the non-secure romloader without that *.auth and SLA_Challenge.dll stuff. Plus we have a CFI-flash driver for the Compal phones, which might work on the MTK platform with a few modifications. If that works, we could flash U-Boot without any proprietary Flashtool/DownloadAgent. Regards, Steve