Downgrade Firmware
Original authors @serrj-sv and @rezmus. Discuss here.
Gateway keeps the previous firmware before the update and you can be loaded from it.
If you update twice to a bad firmware, this method does not work.
If you have bad firmware from the factory - this method does not work.
- Open Gateway
- Solder USB UART adapter (GND to GND, RX to TX, TX to RX)
- Connect adapter to USB. UART setting: 38400 8n1, disable flow control (rts/cts)
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Power gateway with build-in USB power
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Сheck if boot is OK and there are no artifacts in console. If there are artifacts - check the wires, change the USB UART.
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Turn off gateway power
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Connect TP17 to ground (example USB case)
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Power gateway with build-in USB power
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Remove TP17/GND wire after
<RealTek>shows in console.
Attention: ALWAYS keep all UART logs and/or backups!
- Enable flash
<RealTek>snwbi
- Read boot_info to from nand to memory
<RealTek>snwbrecc a0000000 140 40
- Display boot_info in memory
<RealTek>db a0000000 40
[Addr] .0 .1 .2 .3 .4 .5 .6 .7 .8 .9 .A .B .C .D .E .F
A0000000: 7C 91 00 00 E4 58 01 01 01 01 00 20 EC 04 C8 CF |....X..... ....
A0000010: 00 00 20 EC 04 CB 19 00 00 82 80 04 62 C6 00 00 .. .........b...
A0000020: 9A 40 04 72 E8 00 00 00 01 31 2E 30 2E 32 2E 30 [email protected]
A0000030: 30 35 00 00 00 00 00 FF FF FF FF FF FF FF FF FF 05..............
- Copy first line to this calculator:
7C 91 00 00 E4 58 01 01 01 01 00 20 EC 04 C8 CF
It should change 6 bytes:
__ __ __ __ XX XX YY YY YY YY __ __ __ __ __ __
- Paste response from calculator:
<RealTek>eb a000000 7C 91 00 00 E6 5A 00 00 00 00 00 20 EC 04 C8 CF
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Check changes. Repeat step 3. The first line should be changed
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???
<RealTek>snwbeb 140
- Write boot_info from memory to nand
<RealTek>snwbwecc A0000000 140 40
- Reboot gateway (power off/on)
Gateway should starts with previous firmware.