Hello,

we are using Carambola 2 board with WLAN and serial port only. It is important for us to use UBoot console on startup with the serial port. No problem with USB/serial on the 8devices development board (the drawing shows RTS/CTS left unconnected). Now we try to use another Carambola 2 with our own board (RXD/TXD connected, RTS/CTS left open, not ETH, no USB, LED0 LED to H 3.3V, LED5 as Reset L output for a gate). Ups, an older UBoot, no response on key after "Hit any key to stop autoboot:" and it is booting Linux. With booted Linux we are able to use the serial console.

My questions:

Is that a known issue with old UBoot?
Is it possible to activate the old UBoot console, maybe from Linux?
Is it possible to flash a newer UBoot from Linux (very dangerous, I know)?

Regards, Mike.



The boot message from the newer UBoot on the 8devices development board:

U-Boot 1.1.4-g6452b07f-dirty (Jun 13 2013 - 15:49:24)

=====================================
CARAMBOLA2 v1.0 (AR9331) U-boot
http://www.8devices.com/
-------------------------------------
DRAM: 64 MB
Flash: 16 MB
Net: eth0, eth1
=====================================

Hit ESC key to stop autoboot: 0



The boot message from the older UBoot on our Carambola 2 board:

U-Boot 1.1.4 (Feb 8 2013 - 11:41:32)

AP121-2MB (ar9330) U-boot
DRAM:
sri
ar7240_ddr_initial_config(145): python ddr init
#### TAP VALUE 1 = f, 2 = 10
64 MB
Top of RAM usable for U-Boot at: 84000000
Reserving 212k for U-Boot at: 83fc8000
Reserving 192k for malloc() at: 83f98000
Reserving 44 Bytes for Board Info at: 83f97fd4
Reserving 36 Bytes for Global Data at: 83f97fb0
Reserving 128k for boot params() at: 83f77fb0
Stack Pointer at: 83f77f98
Now running in RAM - U-Boot at: 83fc8000
Flash Manuf Id 0xef, DeviceId0 0x40, DeviceId1 0x18
flash size 16777216, sector count = 256
Flash: 16 MB
In: serial
Out: serial
Err: serial
Net: ag7240_enet_initialize...
Fetching MAC Address from 0x83fec1a8
Fetching MAC Address from 0x83fec1a8
: cfg1 0x5 cfg2 0x7114
eth0: 00:00:00:00:00:00
eth0 up
: cfg1 0xf cfg2 0x7214
eth1: 00:00:00:00:00:00
athrs26_reg_init_lan
ATHRS26: resetting s26
ATHRS26: s26 reset done
eth1 up
eth0, eth1
Hit any key to stop autoboot: 0

Meanwhile we do not have a solution but a partial explanation.

I wrote that we are using LED5/GPIO16 L/0V as a gate. We are using the serial port with an echoing HW, switched on with LED4 H, but wish to have non echoing UBoot access, too. The latter is used for semifast flashing our customized Linux + our App over serial line with 230400 Baud. This is for manufacturing and update option without WLAN (and without ETHx, see my first post).

With the 8devices development board and newer UBoot LED5 is L after Reset and remains L, regardless if UBoot or Linux is running.
With older Carambola 2 (older UBoot) this is H and remains H until Linux is started which switch it to L.

Can someone from 8devices confirm this?
Is it a HW/SW issue or SW (UBoot) only?

In Carambola2.pdf documentation LED5/GPIO16 is "Bootstrap L".
If we order Carambola2, do you ensure now LED5/GPIO16 Bootstrap L?

Thank you for attention,
Mike.

Can someone from 8devices confirm this?
Is it a HW/SW issue or SW (UBoot) only?

IMHO Uboot SW

Solved.

Since it is very easy to disable our HW gate - setting one testpoint to GND - I tried the newer UBoot from the Carambola 2 development board.

I had to modify our own serial flash SW to load UBoot + Environment from mtd0/1 dump, add CRC32 checksum checking for safety, flash the dump, and voila, it runs: LED5 remains low during boot, UBoot is accessible with our own HW.

Thank you very much,
Mike.