diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 4ecfac227865..a50038a45250 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -452,6 +452,11 @@ static const struct sfp_quirk sfp_quirks[] = {
 	// Rollball protocol to talk to the PHY.
 	SFP_QUIRK_F("FS", "SFP-10G-T", sfp_fixup_fs_10gt),
 
+	// Fiberstore GPON-ONU-34-20BI can operate at 2500base-X, but report 1.2GBd
+	// NRZ in their EEPROM
+	SFP_QUIRK("FS", "GPON-ONU-34-20BI", sfp_quirk_2500basex,
+		  sfp_fixup_ignore_tx_fault),
+
 	SFP_QUIRK_F("HALNy", "HL-GSFP", sfp_fixup_halny_gsfp),
 
 	// HG MXPD-483II-F 2.5G supports 2500Base-X, but incorrectly reports