diff --git a/configs/mainnet/altair.yaml b/configs/mainnet/altair.yaml
index f30e9fcdc..8b470814f 100644
--- a/configs/mainnet/altair.yaml
+++ b/configs/mainnet/altair.yaml
@@ -37,7 +37,7 @@ DOMAIN_SYNC_COMMITTEE: 0x07000000
 # ---------------------------------------------------------------
 ALTAIR_FORK_VERSION: 0x01000000
 # TBD
-ALTAIR_FORK_SLOT: 0
+ALTAIR_FORK_SLOT: 18446744073709551615
 
 
 # Sync protocol
diff --git a/configs/minimal/altair.yaml b/configs/minimal/altair.yaml
index afdaf9eb5..ceda44a48 100644
--- a/configs/minimal/altair.yaml
+++ b/configs/minimal/altair.yaml
@@ -37,7 +37,7 @@ DOMAIN_SYNC_COMMITTEE: 0x07000000
 # ---------------------------------------------------------------
 ALTAIR_FORK_VERSION: 0x01000000
 # [customized]
-ALTAIR_FORK_SLOT: 0
+ALTAIR_FORK_SLOT: 18446744073709551615
 
 
 # Sync protocol