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This article is about how to use TF or SD card to make Exynos 4412 u-boot boot disk under Ubuntu, the editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article.

First of all, we should be clear that the TF/ SD card can be regarded as a completely blank "blank paper". The reason why there is a difference between partition and partition format is that some data is written in some specific places of this "blank paper" to indicate the partition and partition format.

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* @ author Maoxiao Hu

* @ version V1.0.0

* @ date Feb-2015

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Hardware: iTop 4412 Elite Edition & TF Card

Software: the system can bring its own terminal.

Second, we should also be aware that in TF/SD boot mode, as soon as exynos 4412 is powered on, the internal iROM reads 8KB data from the first Block of TF/SD (starting with the 512th byte) to the internal iRAM, and then runs from the 0 address of the internal iRAM.

The principle is clear, so the first thing you need to do is to format TF/SD at a low level-all Block write zeros.

1. Connect the TF/ SD card and open the terminal.

Use the ls / dev/sd* command to view all disks connected to the computer.

Question: why not use the df command here?

The reason is that if your TF/ SD card has only one partition but this partition is damaged, or there are multiple partitions but no recognized partition, then the df command cannot see the tf/ SD card, so it is the ultimate solution to list all the devices at the beginning of sd under dev directly.

(1) suppose your tf/ SD card has only one partition, regardless of whether the partition is damaged or not, the phenomenon should be similar to this:

Before plugging in the tf/ SD card:

After plugging in the tf/ SD card:

It is obvious that the extra / dev/sdb is the object of subsequent operations in this article.

(2) suppose your tf/ SD card already has multiple partitions, regardless of whether these partitions are damaged or not, the phenomenon should be similar to this:

Before plugging in the tf/ SD card:

After plugging in the tf/ SD card:

There are five more devices here, but we still use / dev/sdb as the object for the rest of this article.

Note: I am / dev/sdb here, but there may be other symbols such as / dev/sdc, etc. You must do the following according to your actual device name, otherwise it may damage the system partition, very important, remember!

2. Use hexadecimal mode to open TF card to view data (can be skipped)

We use the linux native command hexdump to view the data in the tf/ SD card:

The command is:

Sudo hexdump-n 1048576 / dev/sdb

Where-n 1048576 represents the previous 1M=1024*1024=1048576 bytes of data printed out.

The implementation result (part) is as follows:

* the representative content is 0x00, which is omitted in order to save space.

3. Clear the data of the front 1MB on the TF card

Since the uboot size of 4412 is basically on the order of a few hundred kB, clearing unprecedented 1MB space is sufficient, so note that emptying here is not formatting, but filling 0x00.

We use the zero equipment under the system / dev to clear the TF / sd card before 1MB.

The implementation results are as follows:

The count=2000 here represents emptying 2000 block, and one block=512B,2000 happens to be 1MB.

Check the tf/ SD card data by hexdump again and find:

The pre-1MB space was cleared 0 successfully.

4. Burn and write uboot startup files

Here, the file we want to burn is u-boot-iTOP-4412.bin.

Terminal executes commands:

If represents the input file address, based on the actual address of your u-boot-iTOP-4412.bin file, of represents the output address, and the actual equipment number of your tf/ SD card shall prevail.

At this point, you can insert the tf/ SD card into the development board to power up, and in order to prove that we burn and write correctly, we perform the follow-up operations.

5. Make sure that the burning writing is correct (can be skipped)

We need to make sure that the u-boot-iTOP-4412.bin file is correctly burned from the first block of the tf/ SD card. Let's compare it with the same command as hexdump.

Here, for the convenience of display, we only print the pre-5KB data and find that the bin file has been correctly copied to the 512 bytes of the SD card:

6. Connect the TF card to the development board, select TF to start the dial switch, and power on:

The above is how to use TF or SD card to make Exynos 4412 u-boot boot disk under Ubuntu. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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