diff --git a/src/vma.rs b/src/vma.rs
index 518de8a..63ee3b5 100644
--- a/src/vma.rs
+++ b/src/vma.rs
@@ -22,7 +22,7 @@ const VMA_MAX_CONFIGS: usize = 256;
 
 /// Maximum number of block devices
 /// See VMA Header in pve-qemu.git/vma_spec.txt
-const VMA_MAX_DEVICES: usize = 256;
+pub const VMA_MAX_DEVICES: usize = 256;
 
 /// VMA magic string
 /// See VMA Header in pve-qemu.git/vma_spec.txt
diff --git a/src/vma2pbs.rs b/src/vma2pbs.rs
index 37ea308..a888a7b 100644
--- a/src/vma2pbs.rs
+++ b/src/vma2pbs.rs
@@ -24,7 +24,7 @@ use proxmox_time::epoch_to_rfc3339;
 use scopeguard::defer;
 use serde_json::Value;
 
-use crate::vma::VmaReader;
+use crate::vma::{VmaReader, VMA_MAX_DEVICES};
 
 const VMA_CLUSTER_SIZE: usize = 65536;
 
@@ -165,20 +165,21 @@ where
 fn register_block_devices<T>(
     vma_reader: &VmaReader<T>,
     pbs: *mut ProxmoxBackupHandle,
-) -> Result<[Option<BlockDeviceInfo>; 256], Error>
+) -> Result<[Option<BlockDeviceInfo>; VMA_MAX_DEVICES], Error>
 where
     T: Read,
 {
-    let mut block_device_infos: [Option<BlockDeviceInfo>; 256] = [None; 256];
+    let mut block_device_infos: [Option<BlockDeviceInfo>; VMA_MAX_DEVICES] =
+        [None; VMA_MAX_DEVICES];
     let mut pbs_err: *mut c_char = ptr::null_mut();
 
-    for device_id in 0..255 {
-        if !vma_reader.contains_device(device_id) {
+    for (device_id, block_device_info) in block_device_infos.iter_mut().enumerate() {
+        if !vma_reader.contains_device(device_id.try_into()?) {
             continue;
         }
 
-        let device_name = vma_reader.get_device_name(device_id)?;
-        let device_size = vma_reader.get_device_size(device_id)?;
+        let device_name = vma_reader.get_device_name(device_id.try_into()?)?;
+        let device_size = vma_reader.get_device_size(device_id.try_into()?)?;
 
         println!(
             "DEV: dev_id={} size: {} devname: {}",
@@ -198,12 +199,10 @@ where
             handle_pbs_error(pbs_err, "proxmox_backup_register_image")?;
         }
 
-        let block_device_info = BlockDeviceInfo {
+        *block_device_info = Some(BlockDeviceInfo {
             pbs_device_id: pbs_device_id as u8,
             device_size,
-        };
-
-        block_device_infos[device_id as usize] = Some(block_device_info);
+        });
     }
 
     Ok(block_device_infos)
@@ -351,7 +350,7 @@ where
 
     let mut pbs_err: *mut c_char = ptr::null_mut();
 
-    for block_device_info in block_device_infos.iter().take(255) {
+    for block_device_info in block_device_infos {
         let block_device_info = match block_device_info {
             Some(block_device_info) => block_device_info,
             None => continue,