[rastik]

Originally Posted by yifanlu

You have only two viable options. Unfortunately both are untested. 1) USB download mode. You should find the imx50 USB programmer from freescale's website. I don't know if it will work. I never tried it. 2) use fastboot. I see you didn't get it working. It's most likely my fault. I coded it blindly, so you may want to take a look at the c source and see if it's interpreting the input correctly. Join the kindle dev irc chat and when I'm on, I can help you.

USB download mode doesn't seem viable know, I'll keep it for later.
With fastboot flash I see it correctly sends download and flash commands. I know that writing system partition has to be changed, because uboot has a buffer of size 0x5e00000 only. And it is not enough for 15e00000 size of system partition.
When looking into mx50_yoshi_board.h from uboot sources, everything is written to partition 0:

static const struct partition_info_t partition_info[] = {
    {
	.name = "bootloader",
	.address = 0,
	.size = (376*1024), /* 376 KiB */
	.partition = 1,
    },
    {
	.name = "prod",
	.address = 0x0, /* overlap with bootloader */
	.size = (120*1024), /* 120 KiB */
	.partition = 1,
    },
    {
	.name = "bist",
	.address = CONFIG_MMC_BIST_ADDR, /* overlap with bootloader */
	.size = CONFIG_MMC_BIST_SIZE, /* 256 KiB */
	.partition = 1,
    },
    {
	.name = "userdata",
	.address = CONFIG_MMC_USERDATA_ADDR,
	.size = CONFIG_MMC_USERDATA_SIZE,  /* 5 KiB */
	.partition = 1,
    },
    {
    .name = "userpartition",
    .address = 0,
    .size = PARTITION_FILL_SPACE,  /* based on MMC size */
    .partition = 0,
    },
    {
	.name = "mbr",
	.address = 0,
	.size = 1024,  /* 1 KiB */
	.partition = 0,
    },
    {
	.name = "kernel",
	.address = CONFIG_MMC_BOOTFLASH_ADDR,
	.size = CONFIG_MMC_BOOTFLASH_SIZE,  /* 14 MiB */
	.partition = 0,
    },
    {
	.name = "diags_kernel",
	.address = CONFIG_MMC_BOOTDIAGS_ADDR,
	.size = CONFIG_MMC_BOOTFLASH_SIZE,  /* 14 MiB */
	.partition = 0,
    },
    {
	.name = "system",
	.address = 0x2000000,
	.size = (350*1024*1024),  /* 350 MiB */
	.partition = 0,
    },
    {
	.name = "diags",
	.address = 0x17E00000,
	.size = (64*1024*1024),  /* 64 MiB */
	.partition = 0,
    },
    {
	.name = "data",
	.address = 0x1BE00000,
	.size = PARTITION_FILL_SPACE,  /* based on MMC size */
	.partition = 0,
    }
};

No luck with irc now, will try later.