diff --git a/.gitmodules b/.gitmodules
index 094afd43f..e79e14fd3 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,3 @@
-[submodule "3rdparty/fixed"]
-	path = 3rdparty/fixed
-	url = https://gitlab.com/ckamm/fixed.git
 [submodule "3rdparty/anchor"]
 	path = 3rdparty/anchor
 	url = https://github.com/openbook-dex/anchor.git
diff --git a/3rdparty/fixed b/3rdparty/fixed
deleted file mode 160000
index 95bf614b0..000000000
--- a/3rdparty/fixed
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 95bf614b09742333451e073704f11ea502d4563b
diff --git a/Cargo.lock b/Cargo.lock
index ee5fed424..41cd1f89d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1824,13 +1824,12 @@ dependencies = [
 [[package]]
 name = "fixed"
 version = "1.11.0"
+source = "git+https://github.com/blockworks-foundation/fixed.git?branch=v1.11.0-borsh0_10-mango#01516ae3e29418feb066b67830540aa81d04df05"
 dependencies = [
- "arbitrary",
  "az",
- "borsh 0.9.3",
+ "borsh 0.10.3",
  "bytemuck",
  "half",
- "num-traits",
  "serde",
  "typenum",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index c22211362..c7fa3207f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,7 @@ members = [
 anchor-client = "0.28.0"
 anchor-lang = "0.28.0"
 anchor-spl = "0.28.0"
-fixed = {path = "./3rdparty/fixed", version = "1.11.0"}
+fixed = { git = "https://github.com/blockworks-foundation/fixed.git", branch = "v1.11.0-borsh0_10-mango" }
 pyth-sdk-solana = "0.8.0"
 solana-account-decoder = "~1.16.1"
 solana-client = "~1.16.1"
diff --git a/programs/openbook-v2/src/i80f48.rs b/programs/openbook-v2/src/i80f48.rs
new file mode 100644
index 000000000..75da25df6
--- /dev/null
+++ b/programs/openbook-v2/src/i80f48.rs
@@ -0,0 +1,10 @@
+use fixed::types::I80F48;
+
+// regression test for https://gitlab.com/tspiteri/fixed/-/issues/57
+// see https://github.com/blockworks-foundation/fixed/issues/1
+#[test]
+fn bug_fixed_comparison_u64() {
+    let a: u64 = 66000;
+    let b: u64 = 1000;
+    assert!(I80F48::from(a) > b); // fails!
+}
diff --git a/programs/openbook-v2/src/lib.rs b/programs/openbook-v2/src/lib.rs
index d6a911332..e3deb4d01 100644
--- a/programs/openbook-v2/src/lib.rs
+++ b/programs/openbook-v2/src/lib.rs
@@ -18,6 +18,7 @@ pub mod pubkey_option;
 pub mod state;
 pub mod token_utils;
 pub mod types;
+mod i80f48;
 
 #[cfg(feature = "enable-gpl")]
 pub mod instructions;