Update md.asm

- Fix typo
- Propagate flash write fix to flash erase routine

Source/HBIOS/md.asm

@@ -816,7 +816,7 @@ MD_FNCALL:
 	LD	HL,MD_FNRET		; ADDRESS RELOCATABLE CODE TO RETURN TO
 	HB_DI
 	LD	(FF_SAVSTK),SP		; SAVE CURRENT STACK
-	LD	SP,(HBX_BUF_END-2	; SETUP A NEW HIMEM STACK AT END OF HX_BUF
+	LD	SP,HBX_BUF_END-2	; SETUP A NEW HIMEM STACK AT END OF HX_BUF
 	EX	(SP),HL			; BEHIND CODE WITH RETURN ADDRESS PREPOPULATED
 	JP	HBX_BUF			; EXECUTE RELOCATED CODE
 MD_FNRET:
@@ -956,8 +956,8 @@ MD_FERAS_R:				; THIS CODE GETS RELOCATED TO HIGH MEMORY
 	LD	A,$30			; SECTOR ERASE
 	LD	(HL),A			; COMMAND
 ;
-	LD	A,(HL)			; DO TWO SUCCESSIVE READS
-MD_WT4:	LD	C,(HL)			; FROM THE SAME FLASH ADDRESS.
+MD_WT4:	LD	A,(HL)			; DO TWO SUCCESSIVE READS
+	LD	C,(HL)			; FROM THE SAME FLASH ADDRESS.
 	XOR	C			; IF THE SAME ON BOTH READS
 	BIT	6,A			; THEN ERASE IS COMPLETE SO EXIT.
 ;