掌機 - Neo Geo X v370 - SD0開機


如何在新版本的掌機上透過MicroSD開機呢？查看君正的資料手冊後，發現有SD card: MSC0的選項，這個選項應該就是SD0，而預設的開機選項則是Nand flash at CS1


後來發現國外網站有高手提供測試點位置，如下所示


接著焊接這一些接腳並使用SDCard轉接卡當作母座



U-Boot程式位於https://drive.google.com/file/d/0BzVU0vOuWe-sbXZxYXlQcWtJX2M/edit?usp=sharing檔案中，那該如何解開呢？可以使用國外高手提供的程式碼 

/* 
    sys_update_file_extract version 0.1
    gcc -o sys_update_file_extract sys_update_file_extract.c
    This will extract the sys_update_file from neo geo x into the following files 
    uboot.bin = boot loader + partition table
    kernel1.bin = 1st kernel
    kernel2.bin = 2nd kernel
    rootfs.bin = partition 1, normally the root filesystem
    appfs.bin = partition 2, normally mounted to /usr/mtdblock3
    cfgfs.bin = partition 3, normally mounted to /usr/mtdblock4
*/
#include <unistd.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

#define HEADER_SIZE 0x104;

uint64_t get_num(FILE *in);
void write_file(FILE *in, char *outfile, uint64_t offset, uint64_t length);

typedef struct {
    uint64_t sd_offset;    // sd card offset where this chunk would be written
    uint64_t sys_offset;   // offset in sys_update_file where this chunk begins
    uint64_t length;       // length of this chunk
} chunk;

int main(void)
{
    FILE *in;
    int i = 0;
    int sysver;
    chunk uboot, kernel1, kernel2, rootfs, appfs, cfgfs;

    in = fopen("sys_update_file","r");
    if (in == NULL) {
        printf("ERROR: unable to open sys_update_file");
        exit(1);
    }

    uboot.length = get_num(in);
    uboot.sys_offset = HEADER_SIZE;

    kernel1.length = get_num(in);
    kernel1.sys_offset = uboot.sys_offset +    uboot.length;

    kernel2.length = get_num(in);
    kernel2.sys_offset = kernel1.sys_offset + kernel1.length;

    rootfs.length = get_num(in);
    rootfs.sys_offset = kernel2.sys_offset + kernel2.length;

    appfs.length = get_num(in);
    appfs.sys_offset = rootfs.sys_offset + rootfs.length;

    cfgfs.length = get_num(in);
    cfgfs.sys_offset = appfs.sys_offset + appfs.length;

    sysver = get_num(in);

    uboot.sd_offset = get_num(in) << 20;
    kernel1.sd_offset = get_num(in) << 20;
    kernel2.sd_offset = get_num(in) << 20;
    rootfs.sd_offset = get_num(in) << 20;
    appfs.sd_offset = get_num(in) << 20;
    cfgfs.sd_offset = get_num(in) << 20;

    printf("sys_update_file version: %d\n", sysver);
    printf("uboot:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", uboot.sys_offset, uboot.length, uboot.sd_offset);
    write_file(in, "uboot.bin", uboot.sys_offset, uboot.length);

    printf("kernel1:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", kernel1.sys_offset, kernel1.length, kernel1.sd_offset);
    write_file(in, "kernel1.bin", kernel1.sys_offset, kernel1.length);

    printf("kernel2:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", kernel2.sys_offset, kernel2.length, kernel2.sd_offset);
    write_file(in, "kernel2.bin", kernel2.sys_offset, kernel2.length);

    printf("root fs:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", rootfs.sys_offset, rootfs.length, rootfs.sd_offset);
    write_file(in, "rootfs.bin", rootfs.sys_offset, rootfs.length);

    printf("app fs:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", appfs.sys_offset, appfs.length, appfs.sd_offset);
    write_file(in, "appfs.bin", appfs.sys_offset, appfs.length);

    printf("cfg fs:\n    sys offset: %ld\n    length: %ld\n    sd offset: %ld\n", cfgfs.sys_offset, cfgfs.length, cfgfs.sd_offset);
    write_file(in, "cfgfs.bin", cfgfs.sys_offset, cfgfs.length);

    fclose(in);
    return 0;
}

// write out the chunk of data to the passed filename
void write_file(FILE *in, char *outfile, uint64_t offset, uint64_t length)
{
    char buffer[2048];
    int size, left;
    FILE *out;

    out = fopen(outfile, "w");
    if (out == NULL) {
        printf("ERROR: unable to open %s for writing\n", outfile);
        exit(1);
    }

    fseek(in, offset, SEEK_SET);

    left = length;
    while (left > 0) {
        size = fread(buffer, 1, (left > 2048 ? 2048 : left), in);
        fwrite(buffer, 1, size, out);
        left -= size;
    }
    fclose(out);
}

/*
    Each chunk from the header is 20 bytes long
    bytes 1-10 are a string + \0 thats a number
    bytes 11-20 are unknown, but all of them are the following in hex
    FF 00 90 A3 04 08 84 6E 98 BF

    This function returns the number from bytes 1-10
*/
uint64_t get_num(FILE *in)
{
    char buffer[20];
    uint64_t value;

    if (fread(buffer, 1, 20, in) != 20) {
        printf("Error reading from file\n");
        exit(0);
    }
    if (sscanf(buffer, "%ld", &value) != 1) {
        printf("Error parsing number\n");
        exit(0);
    }
    return value;
}

把編譯後的執行檔和sys_update_file放在一起，然後執行編譯後的執行檔即可做解壓縮的動作，接著使用WinHEX將uboot.bin直接Clone寫到SDCard即可，司徒目前是使用2GB SDCard做測試

Baudrate 57600bps 

SD card found!
init ok

U-Boot 1.1.6-ga9493686 (Nov 19 2012 - 09:47:30)
Board: Umido@SNK (CPU Speed 1020 MHz)
DRAM:  256 MB
Error: Unknown flash ID, force set to 'SST_ID_39SF040'
Flash: 512 kB
NAND:nand_get_flash_type: No NAND device found!!!
NAND device: dev_id: 0x0000 ext_id: 0x000000 not known!
nand_scan: No NAND device found!!!
0 MiB
SD init ok
*** Warning - MMC/SD first load, using default environment

-=-=-=-= 0x8ff7f000 -=-=-=-
jz4750_lcd.c 1439
usb status is 0
read vbat value is 3734
usb status is 0
SNK go go go!
act8600: Write register --00000080
data: 00000024
act8600: Read register --00000081
data: 00000005
act8600: Write register --00000081
data: 00000081
LCD quick disable timeout!
jz4750_lcd.c 1385
jz4750_lcd.c 1488
pix clk is 12142857
In jz4750fb_deep_set_mode
pix clk is 12142857
jz4750_lcd.c 1500
LCD quick disable timeout!
pix clk is 12142857
jz4750_lcd.c 1515
usb status is 0
usb status is 0
jz4750_lcd.c 1612
SD init ok

如果是從SD0開機，則會顯示SD card found!，反之則是顯示MMC init ok字樣