When emergency firmware recovery procedure fails, the "dune_firmware_recovery.log" file is created in the root directory of the USB flash drive. This log file contains, among other messages, error code. Below is the list of possible error codes. See here http://files.dune-hd.com/sdk/doc/html/sdk.html, section "Emergency firmware recovery" for details about emergency firmware recovery procedure. ERR A25 ERR A26 Error reading firmware file. ERR A27 ERR A28 ERR A29 ERR A30 ERR A31 ERR A32 ERR A33 ERR A34 ERR A35 ERR A36 ERR A37 ERR A20 ERR A21 ERR A22 ERR A23 ERR A24 ERR A25 ERR A40 Invalid firmware file. ERR A01 ERR A02 Error reading firmware file. ERR A03 Invalid firmware file. ERR A04 ERR A05 Error reading firmware file. ERR A06 Invalid firmware file. The firmware is not suitable for the STB model or it is not allowed to be installed on top of the firmware currently installed on the STB. ERR A07 ERR A08 Invalid firmware file. ERR A38 Invalid firmware file. Too old firmware version is tried to be installed. ERR A09 ERR A10 ERR A11 ERR A17 Invalid firmware file. ERR A18 ERR A39 Firmware version is incompatible with hardware revision. There is no support for STB's hardware revision in the firmware which is tried to be installed. ERR A19 Invalid firmware file. ERR A12 ERR A13 Error reading firmware file. ERR A14 ERR A15 Invalid firmware file. ERR A16 Invalid firmware file size. ERR B01 Unsupported firmware file format. Probably outdated firmware is tried to be installed. ERR B02 Error reading firmware file. ERR B04 Internal error. ERR B05 Error reading firmware file. ERR B06 Internal error. ERR B03 ERR C01 ERR C02 Error reading firmware file. ERR C03 Invalid firmware file. The file has been corrupted/modified. ERR C07 Error reading firmware file. ERR C08 Internal error. ERR C04 Error reading firmware file. ERR C05 Invalid firmware file. The file has been corrupted/modified. ERR C09 Internal error. ERR C10 Invalid firmware file. The file has been corrupted/modified. ERR C06 Error reading firmware file. ERR D01 ERR D02 ERR D03 ERR D11 ERR D12 ERR D13 ERR D21 ERR E01 Error reading/writing NAND flash memory. ERR E21 ERR E31 Error reading firmware file. ERR D31 ERR E41 ERR E42 ERR E51 ERR E52 ERR E53 Error reading/writing NAND flash memory. ERR E05 ERR E06 ERR E07 ERR E10 ERR E11 ERR E15 ERR E16 ERR E17 Internal error. ERR E61 Error reading firmware file. ERR E62 Error reading/writing NAND flash memory. ERR E64 Internal error. ERR E63 ERR E71 ERR E72 ERR E73 ERR Y01 Error reading/writing NAND flash memory. ERR Y02 Invalid firmware file. ERR Y03 Error reading/writing NAND flash memory. ERR Y33 ERR Y04 ERR Y05 ERR Y06 ERR Y07 ERR Y08 ERR Y32 ERR Y09 ERR Y10 ERR Y11 Internal error. ERR Y12 Error reading/writing NAND flash memory. ERR Y13 ERR Y14 Error reading firmware file. ERR Y15 ERR Y16 Invalid firmware file. ERR Y17 Error reading/writing NAND flash memory. ERR Y18 ERR Y19 Error reading firmware file. ERR Y20 Invalid firmware file. ERR Y21 ERR Y22 Error reading/writing NAND flash memory. ERR Y23 Internal error. ERR Y24 ERR Y25 Error reading firmware file. ERR Y26 ERR Y27 ERR Y28 ERR Y29 ERR Y30 ERR Y31 Error reading/writing NAND flash memory. ERR E81 Error reading firmware file. ERR E82 Error reading/writing NAND flash memory.