Allwinner+a133+firmware+work -

You cannot work with A133 firmware using standard Ubuntu repositories. You need the Allwinner "DragonBoard" or "Tina Linux" SDK, or a mainline build environment.

Essential Tools:

Pro Tip: Always enable FEL mode on your PCB design (pulling the BOOT_SEL pin low). 80% of professional Allwinner A133 firmware work involves recovering from a bad boot0 flash.

For many A133 boards, you can boot from a properly formatted SD card. allwinner+a133+firmware+work

  • Use dd to write boot0 to the SD card (offset 8KB): 
    sudo dd if=boot0_sdcard_sun50iw9p1.bin of=/dev/sdX bs=8k seek=1

    • Before writing a single line of code or burning an SD card, you must grasp the A133’s boot ROM flow. The A133 is a legacy of the A64 family but with key differences in power management and DRAM controller.

    Critical Insight for Firmware Work: A bricked A133 is almost never truly dead because the BROM is immutable. You can force USB “FEL Mode” (Download Mode) by shorting the BOOT_SEL pins or holding the FEL button. In FEL mode, the chip waits for a USB command to load a bootloader directly into SRAM.

    | Symptom | Cause | Fix | |--------|-------|-----| | No USB detection | Not in FEL mode | Check FEL pin + GND short | | Stuck at boot0 | Bad DRAM config | Recompile with lower DRAM speed | | Kernel panic | Wrong device tree | Replace .dtb with correct one | | Boot loop after 15 sec | PMIC hold missing | Add hold_power_en in board.dts | You cannot work with A133 firmware using standard

    Emergency recovery: Always keep a known-working firmware .img file. Use PhoenixSuit’s Force Format (uncheck "normal update").

    In the kernel source, append to pwm-backlight node:

    backlight: backlight 
    compatible = "pwm-backlight";
    pwms = <&pwm1 0 1000000 0>; // period 1ms
    brightness-levels = <0 10 20 30 50 100>;
    default-brightness-level = <4>;
    power-supply = <®_backlight>;
;

    Rebuild the kernel: make Image dtbs

    UART0 is your best friend. On a working board, you see:

    HELLO! BOOT0 is starting!
boot0 version: 5.1.0
DRAM CLK = 792 MHz
DRAM Type = 3 (LPDDR3)
DRAM size = 2048 MB
[OK] DRAM init success

    If you get "DRAM init fail" or infinite reboot, your SPL firmware is wrong.

    sunxi-fel boot uboot-with-spl.bin