diff --git a/HelloScript.gm9 b/HelloScript.gm9
index 9c33af1..5303d23 100644
--- a/HelloScript.gm9
+++ b/HelloScript.gm9
@@ -114,6 +114,8 @@ find $[RENPATH] NULL
 sha $[RENPATH] $[TESTPATH].sha
 # Instead of an .sha file you can also use the SHA256 in hex as second argument
 # sha S:/sector0x96.bin 82F2730D2C2DA3F30165F987FDCCAC5CBAB24B4E5F65C981CD7BE6F438E6D9D3
+# This also allows partial SHA checks (for @x:y handling see below)
+# sha S:/firm0.bin@100:100 078CC0CFD850A27093DDA2630C3603CA0C96969BD1F26DA48AC7B1BAE5DD5219
 
 # 'inject' COMMAND
 # This command is used to inject part of one file into another
@@ -122,8 +124,8 @@ sha $[RENPATH] $[TESTPATH].sha
 #                y: origin size, starting at x (in hex)
 #                z: destination offset (in hex)
 # If destination does not exist or z is not given, a new destination file will be created(!)
-# If x is not given, the full origin file size is used to inject
-# If y is not given, everything starting from x is used to inject
+# If x is not given, the full origin file size, starting from offset 0, is used to inject
+# If y is not given, everything starting from offset x is used to inject
 # -n / --no_cancel prevents user cancels (useful on critical operations)
 inject S:/nand_hdr.bin@100:4 $[RENPATH]@200 # offsets and sizes are in hex
 # As we just deliberately corrupted our test file, the subsequent SHA check will fail
diff --git a/source/filesys/fsscript.c b/source/filesys/fsscript.c
index 99a9450..86afb1a 100644
--- a/source/filesys/fsscript.c
+++ b/source/filesys/fsscript.c
@@ -347,6 +347,20 @@ bool parse_line(const char* line_start, const char* line_end, cmd_id* cmdid, u32
 bool run_cmd(cmd_id id, u32 flags, char** argv, char* err_str) {
     bool ret = true; // true unless some cmd messes up
     
+    // process arg0 @string
+    u64 at_org = 0;
+    u64 sz_org = 0;
+    if ((id == CMD_ID_SHA) || (id == CMD_ID_INJECT)) {
+        char* atstr_org = strrchr(argv[0], '@');
+        if (atstr_org) {
+            *(atstr_org++) = '\0';
+            if (sscanf(atstr_org, "%llX:%llX", &at_org, &sz_org) != 2) {
+                if (sscanf(atstr_org, "%llX", &at_org) != 1) at_org = 0;
+                sz_org = 0;
+            }
+        }
+    }
+    
     // perform command
     if (id == CMD_ID_ECHO) {
         ShowPrompt(false, argv[0]);
@@ -384,16 +398,6 @@ bool run_cmd(cmd_id id, u32 flags, char** argv, char* err_str) {
         if (err_str) snprintf(err_str, _ERR_STR_LEN, "move fail");
     } else if (id == CMD_ID_INJECT) {
         char* atstr_dst = strrchr(argv[1], '@');
-        char* atstr_org = strrchr(argv[0], '@');
-        u64 at_org = 0;
-        u64 sz_org = 0;
-        if (atstr_org) {
-            *(atstr_org++) = '\0';
-            if (sscanf(atstr_org, "%llX:%llX", &at_org, &sz_org) != 2) {
-                if (sscanf(atstr_org, "%llX", &at_org) != 1) at_org = 0;
-                sz_org = 0;
-            }
-        }
         u64 at_dst = 0;
         if (atstr_dst) {
             *(atstr_dst++) = '\0';
@@ -438,7 +442,7 @@ bool run_cmd(cmd_id id, u32 flags, char** argv, char* err_str) {
     } else if (id == CMD_ID_SHA) {
         u8 sha256_fil[0x20];
         u8 sha256_cmp[0x20];
-        if (!FileGetSha256(argv[0], sha256_fil)) {
+        if (!FileGetSha256(argv[0], sha256_fil, at_org, sz_org)) {
             ret = false;
             if (err_str) snprintf(err_str, _ERR_STR_LEN, "sha arg0 fail");
         } else if ((FileGetData(argv[1], sha256_cmp, 0x20, 0) != 0x20) && !strntohex(argv[1], sha256_cmp, 0x20)) {
diff --git a/source/filesys/fsutil.c b/source/filesys/fsutil.c
index 5f202bc..06d14ff 100644
--- a/source/filesys/fsutil.c
+++ b/source/filesys/fsutil.c
@@ -136,7 +136,7 @@ size_t FileGetSize(const char* path) {
     return fno.fsize;
 }
 
-bool FileGetSha256(const char* path, u8* sha256) {
+bool FileGetSha256(const char* path, u8* sha256, u64 offset, u64 size) {
     bool ret = true;
     FIL file;
     u64 fsize;
@@ -144,14 +144,17 @@ bool FileGetSha256(const char* path, u8* sha256) {
     if (fvx_open(&file, path, FA_READ | FA_OPEN_EXISTING) != FR_OK)
         return false;
     fsize = fvx_size(&file);
-    fvx_lseek(&file, 0);
+    if (offset + size > fsize) return false;
+    if (!size) size = fsize - offset;
+    fvx_lseek(&file, offset);
     ShowProgress(0, 0, path);
     sha_init(SHA256_MODE);
-    for (u64 pos = 0; (pos < fsize) && ret; pos += MAIN_BUFFER_SIZE) {
+    for (u64 pos = 0; (pos < size) && ret; pos += MAIN_BUFFER_SIZE) {
+        UINT read_bytes = min(MAIN_BUFFER_SIZE, size - pos);
         UINT bytes_read = 0;
-        if (fvx_read(&file, MAIN_BUFFER, MAIN_BUFFER_SIZE, &bytes_read) != FR_OK)
+        if (fvx_read(&file, MAIN_BUFFER, read_bytes, &bytes_read) != FR_OK)
             ret = false;
-        if (!ShowProgress(pos + bytes_read, fsize, path))
+        if (!ShowProgress(pos + bytes_read, size, path))
             ret = false;
         sha_update(MAIN_BUFFER, bytes_read);
     }
diff --git a/source/filesys/fsutil.h b/source/filesys/fsutil.h
index 79aeb34..80ae171 100644
--- a/source/filesys/fsutil.h
+++ b/source/filesys/fsutil.h
@@ -35,7 +35,7 @@ size_t FileGetData(const char* path, void* data, size_t size, size_t foffset);
 size_t FileGetSize(const char* path);
 
 /** Get SHA-256 of file **/
-bool FileGetSha256(const char* path, u8* sha256);
+bool FileGetSha256(const char* path, u8* sha256, u64 offset, u64 size);
 
 /** Find data in file **/
 u32 FileFindData(const char* path, u8* data, u32 size_data, u32 offset_file);
diff --git a/source/godmode.c b/source/godmode.c
index a480228..06e77af 100644
--- a/source/godmode.c
+++ b/source/godmode.c
@@ -789,7 +789,7 @@ u32 Sha256Calculator(const char* path) {
     char pathstr[32 + 1];
     u8 sha256[32];
     TruncateString(pathstr, path, 32, 8);
-    if (!FileGetSha256(path, sha256)) {
+    if (!FileGetSha256(path, sha256, 0, 0)) {
         ShowPrompt(false, "Calculating SHA-256: failed!");
         return 1;
     } else {