diff --git a/boot/boot.asm b/boot/boot.asm
index a10c244..6b94d48 100644
--- a/boot/boot.asm
+++ b/boot/boot.asm
@@ -88,6 +88,50 @@
   %error Must select one FS
 %endif
 
+
+%macro _appenddigitstrdef 2.nolist
+%substr %%ii "0123456789ABCDEF" (%2) + 1
+%strcat _%1 _%1,%%ii
+%endmacro
+
+		; %1 = name of single-line macro to set. will be prefixed by underscore
+		; %2 = number to write
+		; %3 = minimal number of hexits, 0..8. defaults to 1
+		;	(setting it to 0 with a number of 0 defines macro to "")
+%macro _autohexitsstrdef 2-3.nolist 1
+%if %3 > 8
+ %error Minimal number of hexits 9 or more: %3
+%endif
+%define _%1 ""
+%if (%2) >= 1_0000_0000h
+ %error Number has to use 9 or more hexits: %2
+%endif
+%if (%2) >= 1000_0000h || %3 >= 8
+_appenddigitstrdef %1, (%2 >> (7 * 4)) & 0Fh
+%endif
+%if (%2) >= 100_0000h || %3 >= 7
+_appenddigitstrdef %1, (%2 >> (6 * 4)) & 0Fh
+%endif
+%if (%2) >= 10_0000h || %3 >= 6
+_appenddigitstrdef %1, (%2 >> (5 * 4)) & 0Fh
+%endif
+%if (%2) >= 1_0000h || %3 >= 5
+_appenddigitstrdef %1, (%2 >> (4 * 4)) & 0Fh
+%endif
+%if (%2) >= 1000h || %3 >= 4
+_appenddigitstrdef %1, (%2 >> (3 * 4)) & 0Fh
+%endif
+%if (%2) >= 100h || %3 >= 3
+_appenddigitstrdef %1, (%2 >> (2 * 4)) & 0Fh
+%endif
+%if (%2) >= 10h || %3 >= 2
+_appenddigitstrdef %1, (%2 >> (1 * 4)) & 0Fh
+%endif
+%if (%2) >= 1h || %3 >= 1
+_appenddigitstrdef %1, (%2 >> (0 * 4)) & 0Fh
+%endif
+%endmacro
+
                 ; NOTE: sys must be updated if magic offsets change
 	%macro magicoffset 3.nolist
 %ifdef ISFAT12
@@ -102,6 +146,9 @@
 %endif
 %assign NEWOFFSET $ - Entry
 %if NEWOFFSET != SYSOFFSET
+ _autohexitsstrdef NEWOFFSETHEX, NEWOFFSET
+ %strcat _NEWOFFSETHEX _NEWOFFSETHEX,'h'
+ %deftok NEWOFFSET _NEWOFFSETHEX
  %error Magic offset %1 changed for FATFS, old=SYSOFFSET, new=NEWOFFSET
 %endif
 	%endmacro