I have the X6 firmware from here:
https://github.com/johnson442/custom-zyxel-firmware/releases. I have this because in the past I had issues with the modem resyncing at half speed, due to an incompatibility with vectoring (which I have on my line) and the modem.
Unfortunately the modem is resyncing at half speed still.
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VDSL Training Status: Showtime
Mode: VDSL2 Annex B
VDSL Profile: Profile 17a
G.Vector: Enable
Traffic Type: PTM Mode
Link Uptime: 0 day: 9 hours: 6 minutes
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VDSL Port Details Upstream Downstream
Line Rate: 5.968 Mbps 18.645 Mbps
Actual Net Data Rate: 5.941 Mbps 18.646 Mbps
Trellis Coding: ON ON
SNR Margin: 9.9 dB 26.9 dB
Actual Delay: 0 ms 0 ms
Transmit Power: - 1.7 dBm 12.1 dBm
Receive Power: -22.2 dBm -16.9 dBm
Actual INP: 0.0 symbols 49.0 symbols
Total Attenuation: 0.0 dB 24.4 dB
Attainable Net Data Rate: 5.978 Mbps 56.707 Mbps
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VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 9.6 40.5 62.0 N/A N/A 19.2 49.0 85.9
Signal Attenuation(dB): 9.6 39.9 N/A N/A N/A 27.6 48.6 N/A
SNR Margin(dB): 11.5 9.7 N/A N/A N/A 26.9 27.0 N/A
TX Power(dBm): -12.7 -2.1 N/A N/A N/A 10.6 6.6 N/A
====================================================================================
VDSL Counters
Downstream Upstream
Since Link time = 6 min 43 sec
FEC: 3727 356
CRC: 0 15
ES: 0 11
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 15 minutes time = 6 min 9 sec
FEC: 5 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 15 minutes time = 15 min 0 sec
FEC: 0 0
CRC: 0 0
ES: 0 0
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Latest 1 day time = 7 hours 6 min 9 sec
FEC: 120 34
CRC: 0 15
ES: 0 11
SES: 0 0
UAS: 0 0
LOS: 0 0
LOF: 0 0
LOM: 0 0
Previous 1 day time = 24 hours 0 sec
FEC: 11111541 322
CRC: 1384 68
ES: 30 36
SES: 24 4
UAS: 166 151
LOS: 1 0
LOF: 0 0
LOM: 10 0
Total time = 1 days 7 hours 6 min 9 sec
FEC: 160232548 356
CRC: 4823 427
ES: 116 258
SES: 83 4
UAS: 730 668
LOS: 4 0
LOF: 4 0
LOM: 45 0
====================================================================================