There is way to upload firmware using amilda as middle firmware:

1. Download http://midge.vlad.org.ua/misc/amilda-middle.bin
2. Upload this image to original firmware
3. Goto amilda’s web administration (ie, using your web browser enter http://192.168.1.1) and u will see this:

4. Select the Tools tab → Firmware Upgrade

5. Upload your csys image and ... good luck.

Thanks to kamo

Note: The Edimax 6104KP will complain about the amilda-middleware, and won’t upload it. Do *not* try to upload the Sweex image onto this Edimax type-modem: it will brick your Edimax.

Чтобы загрузить Amilda-middleware в 6104KP надо исправить первые 4 символа прошивки HEX-редактором WB4K → WBKP. Без этого Amilda-middleware будет отказываться грузиться в 6104KP. Planet XRT-401D также перешивается с помощью Amilda-middleware.

added “Midge Partition” to /include/asm/adm5120/mx29lv320b.h

        {
                .name =         "Midge Partition",
                .offset =       0x00010000,
                .size =         0x001f0000,
        }

mknod -m666 $(MOUNTPOINT)/dev/mtd_midge b 31 5

void formUpgradeFirmware (webs_t wp, char_t *path, char_t *query) {
    FILE *fh;
    IMG_HEADER_T *pHeader;
    int flag, len;
    int startAddr = -1;

    if (!memcmp(wp->postData, FW_HEADER, SIGNATURE_LEN))
        flag = 1;
    else if (!memcmp(wp->postData, WEB_HEADER, SIGNATURE_LEN))
        flag = 2;
    else {
        websHeader(wp);
        websWrite(wp, "<b>Invalid file format!</b><br>");
        goto finish;
    }

    pHeader = (IMG_HEADER_T*)wp->postData;

    len = pHeader->len;
    len = DWORD_SWAP(len);

    if (flag == 1) {
        if (checksumWord(&wp->postData[sizeof(IMG_HEADER_T)], len) != 0) {
            websHeader(wp);
            websWrite(wp, "<b>Checksum failed in image.</b>");
            goto finish;
        }
    }
    else {
        if (checksumWord(&wp->postData[sizeof(IMG_HEADER_T)], len) != 0) {
            websHeader(wp);
            websWrite(wp, "<b>Checksum failed in image.</b>");
            goto finish;
        }
    }

    if (flag == 1) {
/*      startAddr = CODE_IMAGE_OFFSET;*/
        startAddr = WEB_IMAGE_OFFSET;
    }
    else {
        startAddr = WEB_IMAGE_OFFSET;
    }

    fh = NULL;

    if ( flag == 2)
    {
        fh = fopen(MTD_DEVICE, "w+b");
        fseek(fh, startAddr, SEEK_SET);
    }

    if ( flag == 1) fh = fopen("/dev/mtd_midge", "w+b");

    if (!fh)
    {
            websHeader(wp);
            websWrite(wp, "<b>lol... unknown firmware header</b>");
            goto finish;
    }

    fwrite(wp->postData, sizeof(*(wp->postData)), wp->lenPostData, fh);

    fclose(fh);

    websRedirect(wp, "/reset.php?submit=fwreboot");
    return;
finish:
    websFooter(wp);
    websDone(wp, 200);
}