diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 508b6cc8eddc..2ec91466acdf 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -516,6 +516,15 @@ static void sfp_quirk_ubnt_uf_instant(const struct sfp_eeprom_id *id,
 	{ .vendor = _v, .part = _p, .support = _s, .fixup = _f, }
 #define SFP_QUIRK_S(_v, _p, _s) SFP_QUIRK(_v, _p, _s, NULL)
 #define SFP_QUIRK_F(_v, _p, _f) SFP_QUIRK(_v, _p, NULL, _f)
+/* Like SFP_QUIRK_F, but matches the part as a prefix; the vendor name
+ * is still matched exactly. Use for modules whose EEPROM vendor PN
+ * field reads back with garbage past the legitimate characters instead
+ * of the SFF-8472-mandated space padding, so sfp_strlen can't trim the
+ * field down to the legitimate length.
+ */
+#define SFP_QUIRK_F_PREFIX(_v, _p, _f) \
+	{ .vendor = _v, .part = _p, .support = NULL, .fixup = _f, \
+	  .part_prefix_match = true }
 
 static const struct sfp_quirk sfp_quirks[] = {
 	// Alcatel Lucent G-010S-P can operate at 2500base-X, but incorrectly
@@ -548,6 +557,13 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK("FS", "GPON-ONU-34-20BI", sfp_quirk_2500basex,
 		  sfp_fixup_ignore_tx_fault),
 
+	// Fiberstore XGS-SFP-ONT-MACI is a MAC-mode XGS-PON ONT stick with
+	// ONT-class serial-passthrough TX_FAULT/LOS wiring and slow startup;
+	// mask both signals and extend T_START_UP via the potron fixup. The
+	// PN is the product name (XGS-SFP-ONT-MAC-I) truncated at the 16-byte
+	// field width, so the field is fully occupied and matches exactly.
+	SFP_QUIRK_F("FS", "XGS-SFP-ONT-MACI", sfp_fixup_potron),
+
 	SFP_QUIRK_F("HALNy", "HL-GSFP", sfp_fixup_halny_gsfp),
 
 	SFP_QUIRK_F("H-COM", "SPP425H-GAB4", sfp_fixup_potron),
@@ -608,6 +624,14 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK_S("OEM", "SFP-2.5G-LH20-A", sfp_quirk_2500basex),
 	SFP_QUIRK_F("OEM", "RTSFP-10", sfp_fixup_rollball_cc),
 	SFP_QUIRK_F("OEM", "RTSFP-10G", sfp_fixup_rollball_cc),
+
+	// OEM XGSPONST2001 is an XGS-PON ONT stick with broken TX_FAULT and
+	// LOS indicators and slow startup, just like potron. On cold
+	// power-up the EEPROM vendor PN field reads back with non-printable
+	// garbage past the legitimate string instead of space padding, so
+	// match the part as a prefix.
+	SFP_QUIRK_F_PREFIX("OEM", "XGSPONST2001", sfp_fixup_potron),
+
 	SFP_QUIRK_F("Turris", "RTSFP-2.5G", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10G", sfp_fixup_rollball),
@@ -629,13 +653,16 @@ static size_t sfp_strlen(const char *str, size_t maxlen)
 	return size;
 }
 
-static bool sfp_match(const char *qs, const char *str, size_t len)
+static bool sfp_match(const char *qs, const char *str, size_t len, bool prefix)
 {
+	size_t qs_len;
+
 	if (!qs)
 		return true;
-	if (strlen(qs) != len)
+	qs_len = strlen(qs);
+	if (prefix ? qs_len > len : qs_len != len)
 		return false;
-	return !strncmp(qs, str, len);
+	return !strncmp(qs, str, qs_len);
 }
 
 static const struct sfp_quirk *sfp_lookup_quirk(const struct sfp_eeprom_id *id)
@@ -648,8 +675,9 @@ static const struct sfp_quirk *sfp_lookup_quirk(const struct sfp_eeprom_id *id)
 	ps = sfp_strlen(id->base.vendor_pn, ARRAY_SIZE(id->base.vendor_pn));
 
 	for (i = 0, q = sfp_quirks; i < ARRAY_SIZE(sfp_quirks); i++, q++)
-		if (sfp_match(q->vendor, id->base.vendor_name, vs) &&
-		    sfp_match(q->part, id->base.vendor_pn, ps))
+		if (sfp_match(q->vendor, id->base.vendor_name, vs, false) &&
+		    sfp_match(q->part, id->base.vendor_pn, ps,
+			      q->part_prefix_match))
 			return q;
 
 	return NULL;
diff --git a/drivers/net/phy/sfp.h b/drivers/net/phy/sfp.h
index 879dff7afe6a..19fe29d844a1 100644
--- a/drivers/net/phy/sfp.h
+++ b/drivers/net/phy/sfp.h
@@ -12,6 +12,7 @@ struct sfp_quirk {
 	void (*support)(const struct sfp_eeprom_id *id,
 			struct sfp_module_caps *caps);
 	void (*fixup)(struct sfp *sfp);
+	bool part_prefix_match;
 };
 
 struct sfp_socket_ops {