OSFILE updates it's control block. *RUN works.

auxmem.hostfs.s

@@ -1,8 +1,7 @@
-* FILESYS.S
-*********************************************************
+* AUXMEM.HOSTFS.S
+* (c) Bobbi 2021 GPL v3
+*
 * AppleMOS Host File System
-*********************************************************
-
 
 * OSFIND - open/close a file for byte access
 FINDHND     PHX
@@ -172,7 +171,9 @@ FILEHND     PHX
             PHA
 
             STX   ZP1                 ; LSB of parameter block
+            STX   CBPTR
             STY   ZP1+1               ; MSB of parameter block
+            STY   CBPTR+1
             LDA   #<FILEBLK
             STA   ZP2
             LDA   #>FILEBLK
@@ -247,7 +248,19 @@ FILEHND     PHX
 :S2         >>>   XF2MAIN,LOADFILE
 OSFILERET
             >>>   ENTAUX
-            PLY                       ; Value of A on entry
+            PHA
+            LDA   CBPTR               ; Copy OSFILE CB to :CBPTR addr
+            STA   ZP1
+            LDA   CBPTR+1
+            STA   ZP1+1
+            LDY   #$00
+:L3         LDA   AUXBLK,Y            ; Mainmem left it in AUXBLK
+            STA   (ZP1),Y
+            INY
+            CPY   #18                 ; 18 bytes in control block
+            BNE   :L3
+            PLA
+            PLY                       ; Value of A on OSFILE entry
             CPY   #$FF                ; LOAD
             BNE   :S4                 ; Deal with return from SAVE
 
@@ -291,6 +304,7 @@ OSFILERET
             PLX
             RTS
 
+CBPTR       DW    $0000
 OSFILEM     ASC   'OSFILE($'
             DB    $00
 OSFILEM2    ASC   ')'
@@ -328,7 +342,7 @@ FSCRUN      STX   OSFILECB            ; Pointer to filename
             LDX   #<OSFILECB          ; Pointer to control block
             LDY   #>OSFILECB
             JSR   OSFILE
-*        JMP  (AUXBLK)   ; DOESN'T WORK AS EXPECTED!!!
+            JMP   (OSFILECB+6)        ; Jump to EXEC addr
             RTS
 FSCREN
             LDA   #<OSFSCM

mainmem.s

@@ -409,7 +409,7 @@ LOADFILE    >>>   ENTMAIN
             LDA   FBEXEC             ; If FBEXEC is zero, use addr
             CMP   #$00               ; in the control block
             BEQ   :CBADDR
-* TODOL Load file (without addr) needs to fill in CB
+* TODO: Load file (without addr) needs to fill in CB
             LDA   #<MOSFILE          ; Otherwise use file addr
             STA   GINFOPL+1
             LDA   #>MOSFILE
@@ -424,8 +424,7 @@ LOADFILE    >>>   ENTMAIN
             LDY   GINFOPL+6          ; Aux type MSB
             STY   FBLOAD+1
             STY   FBEXEC+1
-:CBADDR     JSR   PASSADDR           ; Load addr -> code in aux bank
-            LDA   FBLOAD
+:CBADDR     LDA   FBLOAD
             STA   A4L
             LDA   FBLOAD+1
             LDX   :BLOCKS
@@ -449,14 +448,21 @@ LOADFILE    >>>   ENTMAIN
 :EOF2       LDA   OPENPL+5           ; File ref num
             STA   CLSPL+1
             JSR   CLSFILE
-:EXIT       >>>   XF2AUX,OSFILERET
+:EXIT       JSR   COPYFB             ; Copy FILEBLK to auxmem
+            >>>   XF2AUX,OSFILERET
 :BLOCKS     DB    $00
 
-* Stash address in XY to first two bytes of AUXBLK
-PASSADDR    >>>   ALTZP              ; Alt ZP and LC
-            STX   AUXBLK
-            STY   AUXBLK+1
+* Copy FILEBLK to AUXBLK in aux memory
+COPYFB      LDX   #$00
+:L1         LDA   FILEBLK,X
+            TAY
+            >>>   ALTZP              ; Alt ZP and LC
+            TYA
+            STA   AUXBLK,X
             >>>   MAINZP             ; Back to normal
+            INX
+            CPX   #18                ; 18 bytes in FILEBLK
+            BNE   :L1
             RTS
 
 * ProDOS file handling for MOS OSFILE SAVE call
@@ -595,7 +601,8 @@ SAVEFILE    >>>   ENTMAIN
             BCC   :EXIT              ; If close OK
 * TODO: After SAVE CB XY+10..XY+17 needs updating
             LDA   #$02               ; Write error
-:EXIT       >>>   XF2AUX,OSFILERET
+:EXIT       JSR   COPYFB             ; Copy FILEBLK to aux mem
+            >>>   XF2AUX,OSFILERET
 :LEN        DW    $0000
 :BLOCKS     DB    $00