In-Depth Review: Allwinner A133 Firmware Work

1. Partition SD: boot (fat32, 20MB) and rootfs (ext4).
2. Copy to boot:

   # Use Allwinner's dragonboard tool (leaked/binaries available) ./dragon image unpack a133_firmware.img ./output_folder

   • Short the FEL pin (A133 pin TBD – usually LDOA or PH7) to ground.
   • Or use the FEL button if your board has one.
   • Connect USB to PC.
   • Device will appear in PhoenixSuit as "Unknown Device 1".

   Searching for the right firmware for an Allwinner A133 Go to product viewer dialog for this item.

   1. Connect UART (TX/RX/GND) to see boot logs.
   2. Hold FEL button (or short eMMC CLK to GND) and power on.
   3. Check FEL mode: sudo sunxi-fel ver -> Should return "AWUSBFEX".
   4. Erase only U-Boot env (fixes boot loop without full wipe):

      sunxi-fel write 0x44000 zeros.bin  # Overwrite env sector
      

   5. If that fails, dump the full eMMC to a file for analysis:

      sunxi-fel read 0x0 0x1000000 full_emmc_dump.bin
      

   1. BootROM (Mask ROM): Hardwired into the silicon. It checks for bootable media (SD card, NAND, eMMC, SPI NOR) in a defined order.
   2. SRAM (Secure RAM): The BootROM loads the first stage bootloader (usually 32KB) into the A133’s internal SRAM.
   3. SPL (Secondary Program Loader): Initializes clocks, regulators, and the critical DRAM controller (DDR3/DDR4/LPDDR3).
   4. TianoCore / U-Boot: Loads the main bootloader from eMMC/Storage, initializes display, USB, and loads the kernel.
   5. OP-TEE (Optional): The A133 supports TrustZone. Often, firmware work includes loading a secure OS.

   Key fact:

   The A133 does not use UEFI or GRUB. You need livesuit/phoenixsuit or fastboot (if bootloader is intact).

   Workflow: