diff --git a/test/asm/listing/200-overwrite.cfg b/test/asm/listing/200-overwrite.cfg
new file mode 100644
index 000000000..b7b2fee49
--- /dev/null
+++ b/test/asm/listing/200-overwrite.cfg
@@ -0,0 +1,20 @@
+MEMORY
+{
+    A: start = 0, size = 8, file = %O, fill = yes, fillval = $33;
+    B: start = 8, size = 8, file = %O, fill = yes, fillval = $44;
+    C: start = 0, size = 8, file = %O, fill = yes, fillval = $55;
+    D: start = 8, size = 8, file = %O, fill = no,  fillval = $66;
+}
+SEGMENTS
+{
+    A:  load = A, type = ro;
+    B:  load = B, type = ro;
+    C0: load = C, type = ro;
+    C1: load = C, type = ro, start = 5;
+    D:  load = D, type = ro;
+
+    AO: load = A, type = overwrite, start = 4;
+    BO: load = B, type = overwrite, start = 8+5;
+    CO: load = C, type = overwrite, start = 2;
+    DO: load = D, type = overwrite, start = 8+4;
+}
diff --git a/test/asm/listing/200-overwrite.s b/test/asm/listing/200-overwrite.s
new file mode 100644
index 000000000..cd2349c6a
--- /dev/null
+++ b/test/asm/listing/200-overwrite.s
@@ -0,0 +1,29 @@
+; verification of overwrite segment feature
+; See: https://github.com/cc65/cc65/issues/1366
+
+; A: full memory area which is overwritten to the end
+.segment "A"
+.byte 0,1,2,3,4,5,6,7
+.segment "AO"
+.byte $24,$25,$26,$27
+
+; B: incomplete memory area overwritten in the fill area
+.segment "B"
+.byte 0,1,2
+.segment "BO"
+.byte $25,$26
+
+; C: memory area with gap overwritten across the gap
+.segment "C0"
+.byte 0,1,2
+.segment "C1"
+.byte 5,6,7
+.segment "CO"
+.byte $22,$23,$24,$25
+
+; D: incomplete memory area without fill,
+;    but overwrite extends past existing segments
+.segment "D"
+.byte 0,1,2
+.segment "DO"
+.byte $24,$25
diff --git a/test/asm/listing/201-overwrite-overflow.cfg b/test/asm/listing/201-overwrite-overflow.cfg
new file mode 100644
index 000000000..cada57d5a
--- /dev/null
+++ b/test/asm/listing/201-overwrite-overflow.cfg
@@ -0,0 +1,12 @@
+MEMORY
+{
+    A: start = 0, size = 8, file = %O, fill = yes, fillval = $33;
+    B: start = 8, size = 8, file = %O, fill = yes, fillval = $44;
+}
+SEGMENTS
+{
+    A:  load = A, type = ro;
+    B:  load = B, type = ro;
+    AO: load = A, type = overwrite, start = 6;
+    BO: load = B, type = overwrite, start = 8+6;
+}
diff --git a/test/asm/listing/201-overwrite-overflow.s b/test/asm/listing/201-overwrite-overflow.s
new file mode 100644
index 000000000..156388ab5
--- /dev/null
+++ b/test/asm/listing/201-overwrite-overflow.s
@@ -0,0 +1,13 @@
+; verification of overwrite segment overflow cases
+
+; error: overflow past end of A memory area
+.segment "A"
+.byte 0,1,2,3
+.segment "AO"
+.byte $26,$27,$28
+
+; error: overflow past end of B memory area
+.segment "B"
+.byte 0,1,2,3
+.segment "BO"
+.byte $26,$27,$28
diff --git a/test/asm/listing/Makefile b/test/asm/listing/Makefile
index 3c4c404af..204984b64 100644
--- a/test/asm/listing/Makefile
+++ b/test/asm/listing/Makefile
@@ -58,12 +58,20 @@ $(WORKDIR)/$1.bin: $1.s $(ISEQUAL)
 ifeq ($(wildcard control/$1.err),)
 	$(CA65) -t none -o $$(@:.bin=.o) $$< > $$(@:.bin=.err) 2> $$(@:.bin=.err2)
 ifeq ($(wildcard control/$1.no-ld65),)
+ifeq ($(wildcard $1.cfg),)
 	$(LD65) -t none -o $$@ $$(@:.bin=.o) none.lib > $$(@:.bin=.ld65-err) 2> $$(@:.bin=.ld65-err2)
+else
+	$(LD65) -C $$(<:.s=.cfg) -o $$@ $$(@:.bin=.o) none.lib > $$(@:.bin=.ld65-err) 2> $$(@:.bin=.ld65-err2)
+endif
 endif
 else
 	$(CA65) -t none -o $$(@:.bin=.o) $$< > $$(@:.bin=.err) 2> $$(@:.bin=.err2) || $(TRUE)
 ifeq ($(wildcard control/$1.no-ld65),)
+ifeq ($(wildcard $1.cfg),)
 	$(LD65) -t none -o $$@ $$(@:.bin=.o) none.lib > $$(@:.bin=.ld65-err) 2> $$(@:.bin=.ld65-err2) || $(TRUE)
+else
+	$(LD65) -C $$(<:.s=.cfg) -o $$@ $$(@:.bin=.o) none.lib > $$(@:.bin=.ld65-err) 2> $$(@:.bin=.ld65-err2) || $(TRUE)
+endif
 endif
 endif
 
@@ -117,12 +125,20 @@ endif
 ifeq ($(wildcard control/$1.err),)
 	$(CA65) -t none -l $$(@:.bin=.list-lst) -o $$(@:.bin=.list-o) $$< > $$(@:.bin=.list-err) 2> $$(@:.bin=.list-err2)
 ifeq ($(wildcard control/$1.no-ld65),)
+ifeq ($(wildcard $1.cfg),)
 	$(LD65) -t none -o $$(@:.bin=.list-bin) $$(@:.bin=.list-o) none.lib > $$(@:.bin=.list-ld65-err) 2> $$(@:.bin=.list-ld65-err2)
+else
+	$(LD65) -C $$(<:.s=.cfg) -o $$(@:.bin=.list-bin) $$(@:.bin=.list-o) none.lib > $$(@:.bin=.list-ld65-err) 2> $$(@:.bin=.list-ld65-err2)
+endif
 endif
 else
 	$(CA65) -t none -l $$(@:.bin=.list-lst) -o $$(@:.bin=.list-o) $$< > $$(@:.bin=.list-err) 2> $$(@:.bin=.list-err2) || $(TRUE)
 ifeq ($(wildcard control/$1.no-ld65),)
+ifeq ($(wildcard $1.cfg),)
 	$(LD65) -t none -o $$(@:.bin=.list-bin) $$(@:.bin=.list-o) none.lib > $$(@:.bin=.list-ld65-err) 2> $$(@:.bin=.list-ld65-err2) || $(TRUE)
+else
+	$(LD65) -C $$(<:.s=.cfg) -o $$(@:.bin=.list-bin) $$(@:.bin=.list-o) none.lib > $$(@:.bin=.list-ld65-err) 2> $$(@:.bin=.list-ld65-err2) || $(TRUE)
+endif
 endif
 endif
 
diff --git a/test/asm/listing/control/201-overwrite-overflow.err b/test/asm/listing/control/201-overwrite-overflow.err
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/asm/listing/readme.txt b/test/asm/listing/readme.txt
index d6280b954..5436b234a 100644
--- a/test/asm/listing/readme.txt
+++ b/test/asm/listing/readme.txt
@@ -4,6 +4,8 @@ Overall test:
 These testcases can be used to test different aspects of the assembler.
 The name of a test is everything in the form <test>.s.
 
+If a custom linker configuration is needed, also include <test>.cfg. 
+
 The following reference files can be added:
 
 - ref/<test>.bin-ref:
diff --git a/test/asm/listing/ref/200-overwrite.bin-ref b/test/asm/listing/ref/200-overwrite.bin-ref
new file mode 100644
index 000000000..b3a6f4f63
Binary files /dev/null and b/test/asm/listing/ref/200-overwrite.bin-ref differ
diff --git a/test/asm/listing/ref/201-overwrite-overflow.ld65err2-ref b/test/asm/listing/ref/201-overwrite-overflow.ld65err2-ref
new file mode 100644
index 000000000..e372938ef
--- /dev/null
+++ b/test/asm/listing/ref/201-overwrite-overflow.ld65err2-ref
@@ -0,0 +1,3 @@
+ld65: Warning: 201-overwrite-overflow.cfg:3: Segment 'AO' overflows memory area 'A' by 1 byte
+ld65: Warning: 201-overwrite-overflow.cfg:4: Segment 'BO' overflows memory area 'B' by 1 byte
+ld65: Error: Cannot generate most of the files due to memory area overflows
diff --git a/test/asm/readme.txt b/test/asm/readme.txt
index c3198c12a..db7f64504 100644
--- a/test/asm/readme.txt
+++ b/test/asm/readme.txt
@@ -1,32 +1,38 @@
 Assembler Testcases
 ===================
 
-Opcode Tests:
--------------
+cpudetect
+---------
 
-these go into opcodes/. Refer to opcodes/readme.txt
+Tests the --cpu command line option of ca65/ld65.
+Refer to cpudetect/readme.txt
 
 
-CPU Detect Tests
-----------------
+opcodes
+-------
 
-these go into cpudetect/. Refer to cpudetect/readme.txt
+Test of assembler opcodes for each CPU.
+Refer to opcodes/readme.txt
 
 
-Overall tests:
---------------
-
-These go into listing/. Refer to listing/readme.txt
-
-val:
-----
-
-Works very much like the /val directory used to test the compiler -  individual
-tests are run in the simulator and should exit with an exit code of 0 when they
-pass, or either -1 or a number indicating what part of the test failed on error.
-
 err:
 ----
 
-Works very much like the /err directory used to test the compiler - individual
-tests are assembled and MUST NOT assemble without error.
+Used to test assembler errors. These tests MUST NOT assemble without error.
+
+
+listing:
+--------
+
+This is the most versatile assembler test form, allowing control customizations,
+reference tests for binary output, stdout and error text ouput, error tests,
+listings, custom linker configuration, etc. as needed.
+Refer to listing/readme.txt
+
+
+val:
+----
+
+Runtime assembly tests using sim65 that should exit with an exit code of 0 when
+the pass, or either -1 or a number indicating what part of the test failed on
+error.