diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2f8b328..baa009d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 # Change Log
 All notable changes to this project will be documented in this file. This change log follows the conventions of [keepachangelog.com](http://keepachangelog.com/).
 
+## [0.2.277] - 2021-10-25
+### Fixed
+- Non-primitive arguments on upcalls would generate invalid bytecode with `nil` instructions
+
+
 ## [0.2.259] - 2021-10-16
 ### Fixed
 - Long and double arguments to upcalls failed to compile in some cases
@@ -68,6 +73,7 @@ All notable changes to this project will be documented in this file. This change
 - Support for serializing and deserializing arbitrary Clojure functions
 - Support for serializing and deserializing arbitrary Clojure data structures
 
+[0.2.277]: https://github.com/IGJoshua/coffi/compare/v0.2.259...v0.2.277
 [0.2.259]: https://github.com/IGJoshua/coffi/compare/v0.1.251...v0.2.259
 [0.1.251]: https://github.com/IGJoshua/coffi/compare/v0.1.246...v0.1.251
 [0.1.246]: https://github.com/IGJoshua/coffi/compare/v0.1.241...v0.1.246
diff --git a/README.md b/README.md
index 356e991..64afce1 100644
--- a/README.md
+++ b/README.md
@@ -16,8 +16,8 @@ This library is available on Clojars. Add one of the following entries to the
 `:deps` key of your `deps.edn`:
 
 ```clojure
-org.suskalo/coffi {:mvn/version "0.2.259"}
-io.github.IGJoshua/coffi {:git/tag "v0.2.259" :git/sha "ee5805c"}
+org.suskalo/coffi {:mvn/version "0.2.277"}
+io.github.IGJoshua/coffi {:git/tag "v0.2.277" :git/sha "2eec1b1"}
 ```
 
 If you use this library as a git dependency, you will need to prepare the
diff --git a/src/clj/coffi/ffi.clj b/src/clj/coffi/ffi.clj
index 87fe7c2..3862ce4 100644
--- a/src/clj/coffi/ffi.clj
+++ b/src/clj/coffi/ffi.clj
@@ -490,7 +490,7 @@
                        (if (seq types)
                          (let [prim (mem/primitive-type (first types))]
                            (recur (rest types)
-                                  (conj acc [[(load-instructions prim) idx]
+                                  (conj acc [[(load-instructions prim :aload) idx]
                                              (to-object-asm (first types))])
                                   (cond-> (inc idx)
                                     (double-sized? prim)