bugfix: UF2 updater was using wrong flash address

firmware/rust1/src/uf2updater.rs

@@ -219,7 +219,7 @@ impl<const FLASH_SIZE: usize> UF2UpdateHandler<FLASH_SIZE> {
             return;
         }
         let addr_orig = addr;
-        let addr = addr - partitions.flash_start_addr - partitions.active.from + partitions.dfu.to;
+        let addr = addr - partitions.flash_start_addr - partitions.active.from + partitions.dfu.from;
 
         let abort_previous: bool;
         let process_current: bool;