[solved ?] My A20 doesn't want to boot.

[Shadal]

Hi !

It seems I solved my problem while I was writing this post. I hope it will help someone.

I brought out again my A20 a few days ago for new projects after some buggy trials last year.
With a new image on the microSD card (Armbian_5.92.4_Olinuxino-a20_Debian_buster_next_5.2.21.img), the boot was complaining that the all-FF MAC address was illegal. So I used olinuxino config write to set another MAC address... wait, that was my previous post...
So I set a new MAC address, but it was still unable to boot.
I tried with an older image that I used for a previous installation (which used to boot, although I didn't manage to fulfill my projects) and... still not booting:

Code Select Expand

U-Boot SPL 2019.04-armbian (Jun 20 2019 - 14:43:54 +0300)
DRAM: 1024 MiB
CPU: 912000000Hz, AXI/AHB/APB: 3/2/2
EEPROM: Ready
Config: Valid
Trying to boot from MMC1


U-Boot 2019.04-armbian (Jun 20 2019 - 14:43:54 +0300) Allwinner Technology

CPU:  Allwinner A20 (SUN7I)
Model: A20-OLinuXino-LIME2-G2 Rev.G
Serial:00000A48
MAC:  AA:AA:AA:AA:AA:AA
I2C:  ready
DRAM:  1 GiB
NAND:  0 MiB
MMC:  mmc@1c0f000: 0
Loading Environment from EXT4...
** Unable to use mmc 0:auto for loading the env **
HDMI connected: Setting up a 1920x1080 hdmi console (overscan 0x0)
In:    serial
Out:  vga
Err:  vga
Allwinner mUSB OTG (Peripheral)
Net:  eth0: ethernet@1c50000
starting USB...
USB0:  USB EHCI 1.00
USB1:  USB EHCI 1.00
scanning bus 0 for devices... 1 USB Device(s) found
scanning bus 1 for devices... 1 USB Device(s) found
      scanning usb for storage devices... 0 Storage Device(s) found
Hit any key to stop autoboot:  1  0
switch to partitions #0, OK
mmc0 is current device
** Unrecognized filesystem type **
MMC Device 1 not found
no mmc device at slot 1
NAND booting is temporary disabled.
scanning bus for devices...
SATA link 0 timeout.
AHCI 0001.0100 32 slots 1 ports 3 Gbps 0x1 impl SATA mode
flags: ncq stag pm led clo only pmp pio slum part ccc apst

Device 0: unknown device

Device 0: unknown device
ethernet@1c50000 Waiting for PHY auto negotiation to complete......... TIMEOUT !
Could not initialize PHY ethernet@1c50000
ethernet@1c50000 Waiting for PHY auto negotiation to complete......... TIMEOUT !
Could not initialize PHY ethernet@1c50000
I am not very familiar with boot problems as it used to work before and I was fearing a hardware failure... but my last experiments strangely played with segfault and kernel panics and the mess was not fully solved by flashing the microSD.

I flashed my microSD with the oldest image I had, a20-lime2_mainline_uboot_sunxi_kernel_3.4.103_jessie_eMMC_rel_15.img, and... it booted.
Then I flashed the last buster image and... it booted too.

So it works again. If you know why, please tell me.

[JohnS]

I'd vote for a marginal SD or power supply.

John

[Shadal]

I use one of the power supplies from Olimex, and a battery, and the supply has enough power left for a sata hdd (which does not seem to have any effect on boot success or failure. It is detected when it is connected).
I haven't tried any other SD card.
I note that the image that seems to solve the problem has the old 2-partition layout.

[LubOlimex]

This is probably related to the tool you used to prepare the card with the new image, some old data got left over in the first few addresses of the memory of the card and this hinders the boot. Try different strategies for low level formatting of the card before preparing it with a new image.