diff --git a/.gitignore b/.gitignore
index dc03131..854de3e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ build/
 .cache/
 tags
 *.o
+*.out
diff --git a/meson.build b/meson.build
index 1bb3fe7..5604ac5 100644
--- a/meson.build
+++ b/meson.build
@@ -38,3 +38,13 @@ test(
     depends: [bin],
     workdir: meson.project_source_root() / 'tests/STB_GLOBAL_NOCONFLICT'
 )
+
+test(
+    'et_rel_fail', 
+    find_program('python3'), 
+    args : [
+        files('tests/ET_REL_FAIL/tester.py'), bin
+    ],
+    depends: [bin],
+    workdir: meson.project_source_root() / 'tests/ET_REL_FAIL'
+)
diff --git a/src/link.c b/src/link.c
index 57ebb7b..315e112 100644
--- a/src/link.c
+++ b/src/link.c
@@ -9,6 +9,10 @@ bool shared_emachine(uint64_t base, uint64_t input) {
     return base == input;
 }
 
+bool etype_is_et_rel(Elf_header *header) {
+    return header->e_type == ET_REL;
+}
+
 // checks for stb_global symbol collision between files.
 // drains the symtab hashmap and inserts into global hashmap
 // collisions between equal values will crash
@@ -42,6 +46,7 @@ void stb_global_collision(Hashmap **file_symbols, Hashmap **globals, Objdata *fi
 // for linking to succeed:
 //
 // TODO:
+// - [ ] all files are relocatable (eheader->e_type is et_rel)
 // - [x] same e_machine
 // - [x] ensure no global bindings are shared between files
 // undefined external references (every symbol needs to have a corresponding address)
@@ -61,6 +66,9 @@ void validate_objmeta(Objdata *head, Args args) {
         if (!shared_emachine(shared_machine, eheader.e_machine))
             fatal_error("Different e_machine detected");
 
+        if (!etype_is_et_rel(&eheader))
+            fatal_error("File's e_type is not ET_REL");
+
         // we get a copy of allocated symtab because stb_global calls hashmap_pop 
         // which modifies the hashmap.
         Hashmap **symtab_dup = grab_symbol_table(eheader, sheader, args, path);
diff --git a/tests/ET_REL_FAIL/makefile b/tests/ET_REL_FAIL/makefile
new file mode 100644
index 0000000..e62a124
--- /dev/null
+++ b/tests/ET_REL_FAIL/makefile
@@ -0,0 +1,7 @@
+clean:
+	rm *.out
+
+all:
+	gcc program1.c -o p1.out
+	gcc program2.c -o p2.out
+	gcc program3.c -o p3.out
diff --git a/tests/ET_REL_FAIL/program1.c b/tests/ET_REL_FAIL/program1.c
new file mode 100644
index 0000000..7ef391c
--- /dev/null
+++ b/tests/ET_REL_FAIL/program1.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main() {
+    printf("hi meow\n");
+}
diff --git a/tests/ET_REL_FAIL/program2.c b/tests/ET_REL_FAIL/program2.c
new file mode 100644
index 0000000..7ef391c
--- /dev/null
+++ b/tests/ET_REL_FAIL/program2.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main() {
+    printf("hi meow\n");
+}
diff --git a/tests/ET_REL_FAIL/program3.c b/tests/ET_REL_FAIL/program3.c
new file mode 100644
index 0000000..7ef391c
--- /dev/null
+++ b/tests/ET_REL_FAIL/program3.c
@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+int main() {
+    printf("hi meow\n");
+}
diff --git a/tests/ET_REL_FAIL/tester.py b/tests/ET_REL_FAIL/tester.py
new file mode 100755
index 0000000..a22de22
--- /dev/null
+++ b/tests/ET_REL_FAIL/tester.py
@@ -0,0 +1,42 @@
+#!/bin/python3
+
+import subprocess
+import os
+import sys
+
+linker_bin = sys.argv[1]
+
+def test_prom(prom_path: str, bin_path: str, cwd: str):
+    result = subprocess.run(
+        [prom_path, bin_path],
+        capture_output=True, text=True,
+        cwd=cwd
+    )
+    if result.returncode == 0:
+        print(f"failed to identify {bin_path} is not ET_REL")
+        print(result.stdout)
+        print(result.stderr)
+        exit(1)
+
+
+def main():
+    cwd = os.path.dirname(os.path.abspath(__file__))
+
+    result = subprocess.run(
+        ["make", "all", "-C", cwd],
+        capture_output = True, text = True
+    )
+
+    if result.returncode != 0:
+        print("make failed:", result.stderr)
+        sys.exit(1)
+
+    # checking prom against binaries
+
+    for i in range(1,4):
+        test_prom(linker_bin, f"program{i}.out", cwd)
+
+    print("pass")
+
+
+main()