How to boot BPI-M2U/M2B up from SATA device

BPI-M2 Ultra is a powerful Quad-Core ARMv7 based SBC (Single Board Computer) with a powerful Allwinner R40 SoC and 2 GiB DDR3 RAM. BPI-M2 Berry is a Raspberry Pi compatible version of M2U with V40 SoC, an automotive version of R40, and fewer RAM (1 GiB). They are software compatible.

For some reason we want to boot M2U from SATA device for better IO performance. The following photo shown how to connect a SATA HDD to M2U.

M2U_SATA

From design of Allwinner, the default boot devices sequence has been cured in the BOOT ROM of SoC. The priorities of boot devices from high to low are SD card > NAND > eMMC > NOR SPI Flash.

There is no SATA device right? NP, we can load and boot bootloader and U-Boot form a SD card. By setting the kernel cmdline in the uEnv of U-Boot, it will take over the right from SD card to the SATA device at the second boot stage.

So let’s start.

 

First prepare a bootable SD card from official released image, like this.

Then open the 256MiB FAT partition called BPI-BOOT.

Open and edit /bananapi/bpi-m2u/linux/720p/uEnv.txt. Attention: which file you need to edit depend on which bootloader you select with bpi-bootsel, the default bootloader will load the environment configuration from 720P.

Find this part of this file.

root=/dev/mmcblk0p2 rootfstype=ext4 rw rootwait bootmenutimeout=10 datadev=mmcblk0p2
console=earlyprintk=sunxi-uart,0x01c28000 console=tty1 console=ttyS0,115200n8 no_console_suspend consoleblank=0
bootopts=enforcing=1 initcall_debug=0 loglevel=4 init=/init cma=256M panic=10
volumioarg=imgpart=/dev/mmcblk0p2 imgfile=/volumio_current.sqsh rw rootwait

Change the three MMC block device to /dev/sda2, like that.

root=/dev/sda2 rootfstype=ext4 rw rootwait bootmenutimeout=10 datadev=sda2
console=earlyprintk=sunxi-uart,0x01c28000 console=tty1 console=ttyS0,115200n8 no_console_suspend consoleblank=0
bootopts=enforcing=1 initcall_debug=0 loglevel=4 init=/init cma=256M panic=10
volumioarg=imgpart=/dev/sda2 imgfile=/volumio_current.sqsh rw rootwait

Now we have a SD card to boot root file system on  the SATA device.

 

It’s easier to prepare the root filesystem on HDD. Just need to dd the original official released image to the HDD like a SD card. Then expand or resize the root fs like normal. Then power it up.

Now enjoy.

How to adjust the CPU voltage of BPI-M2+

This article introduced how to adjust the VCC-CPUX voltage of the BPI-M2+ with replacing a register of power circuit.

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WARNING!

With any hardware change or component soldering.

You will LOST all warranty of your Banana Pi!

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When I did something system image build and test tasks for the BPI-M2+ with Allwinner H3 before it on stock last year, I have received a Engineer Sample (ES) form SINOVOIP, the manufacturer of Banana Pi.

The Banana Pi Community Forum have received a lot of reports of the too high VCC-CPUX voltage causing horrible heat issue from other developers.

There is a easy to measure the VCC-CPUX voltage of your BPI-M2+.

This picture shows the Test Point (TP: VCPU) of VCC-CPUX.

QQ图片20170426093111

If you get a result like me, Congratulation! You got a ES. (R. I. P. the warranty

 

Okay, the next step is replace the reference register in the feedback circuit of the voltage regulator.

QQ图片20170426093445

QQ图片20170426093459

I have no 0402 register in my component library, so I use the 0805. (I’m sorry for that.

Before:QQ图片20170426093427

After:QQ图片20170426093436

 

And it works. 🙂

QQ图片20170426094321

 

According to the AW’s whitepaper H3 should work at 1.008GHz max_freq, but I tested ok with the 1.2GHz sys_config. Lucky~

photo_2017-04-25_21-52-13

This is the cpuinfo_cur_freq result of running cpuburn-a7 (https://github.com/ssvb/cpuburn-arm/raw/master/cpuburn-a7.S) and corekeeper.sh.

The idle CPU temperature is about 15 degrees Celsius lower than work at 1.4 V.

继续阅读How to adjust the CPU voltage of BPI-M2+