diff --git a/src/libty/firmware.c b/src/libty/firmware.c
index b8e82cf..9c193c1 100644
--- a/src/libty/firmware.c
+++ b/src/libty/firmware.c
@@ -161,10 +161,10 @@ static ssize_t read_memory(int64_t offset, uint8_t *buf, size_t len, void *udata
 
     if (offset < 0)
         offset = ctx->offset;
-    if (offset > ctx->len)
+    if ((size_t)offset > ctx->len)
         return ty_error(TY_ERROR_RANGE, "Cannot seek beyond end of file '%s'", ctx->filename);
 
-    size_t copy_len = _HS_MIN(ctx->len - offset, len);
+    size_t copy_len = _HS_MIN((size_t)ctx->len - (size_t)offset, (size_t)len);
     memcpy(buf, ctx->mem + offset, copy_len);
     ctx->offset += (int64_t)copy_len;
 
diff --git a/src/libty/firmware_elf.c b/src/libty/firmware_elf.c
index 8a29edc..cd4acc0 100644
--- a/src/libty/firmware_elf.c
+++ b/src/libty/firmware_elf.c
@@ -96,7 +96,7 @@ static int read_chunk(struct loader_context *ctx, int64_t offset, void *buf, siz
     r = (*ctx->func)(offset, (uint8_t *)buf, size, ctx->udata);
     if (r < 0)
         return (int)r;
-    if (r < size)
+    if ((size_t)r < size)
         goto truncated;
 
     return 0;
diff --git a/src/libty/firmware_ihex.c b/src/libty/firmware_ihex.c
index 11aa4bb..6340f8a 100644
--- a/src/libty/firmware_ihex.c
+++ b/src/libty/firmware_ihex.c
@@ -155,7 +155,7 @@ int ty_firmware_load_ihex(ty_firmware *fw, ty_firmware_read_func *func, void *ud
 {
     assert(fw);
     assert(!fw->segments_count && !fw->total_size);
-    assert(mem || !len);
+    assert(func);
 
     struct parser_context ctx = {0};
     _HS_ARRAY(uint8_t) buf = {0};