Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!rpi!uupsi!sunic!tut!funic!santra!santra!jraja From: jraja@niksula.hut.fi (Jarno Rajahalme) Newsgroups: comp.sys.amiga.hardware Subject: Re: A1000 Kickstart Questions (for 2.0 hardware hack) Message-ID: Date: 8 Aug 90 17:16:25 GMT References: <90210.130137LEEK@QUCDN.BITNET> Sender: news@santra.uucp (Cnews - USENET news system) Organization: Helsinki University of Technology, Finland Lines: 110 In-Reply-To: LEEK@QUCDN.QueensU.CA's message of 29 Jul 90 17:01:37 GMT In article <90210.130137LEEK@QUCDN.BITNET> LEEK@QUCDN.QueensU.CA writes: > Path: santra!fuug!sics.se!sunic!uupsi!rpi!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!news-server.csri.toronto.edu!qucdn!leek > From: LEEK@QUCDN.QueensU.CA > Newsgroups: comp.sys.amiga.hardware > Date: 29 Jul 90 17:01:37 GMT > Organization: Queen's University at Kingston > Lines: 25 > I am working on a PD hardware project to allow A1000 owners to run 2.0. > -- (yeap !!) > I have some questions... > > Can anyone please tell me when and where the kickstart WCS is write protected ? > Is it in Boot Rom or in Kickstart ? > Write protection is disabled as an consequence of the RESET command. RESET also disables all CHIP-RAM. Following code gets your A1000 in to unprotected mode: * This program switches on the bootROM at $f80000 !!! * And makes KickRAM writeable * * Caution: RESETs your machine!!! move.l #trap0,$80 trap #0 trap0 movea.l $fc0004,a0 ;Of cource works for 256K ROM only :-) reset ;<<<< must be longword aligned (prefetch) jmp (a0) or located in FAST-RAM at runtime! I disassembled the Boot-ROM a little and noticed that Write-Protection is enabled by attempting to write to Boot-ROM's area. To be exact: First the Kickstart is tested (somehow) and if test is succesful all tollowing tests and disk activity is bypassed. If not, the whole system is checked and Kickstart loaded. THEN: (from $f80262) Bootroms address ($f80000) is loaded to a1, Kickstart's entry address (from $fc0004) is loaded to a0, d0 is cleared; following code is moved to stack: move.w d0,(a1) jmp (a0) and then we jump to (sp) (containing the code above!). As the tesult Boot-rom is disabled (and write-protection enabled) and KickStart started. Now there is a conflict here. Because Boot-ROM is located at $f80000 where the new ram should be placed, the ram in the same location is not usable (ofcourse). At first, Boot-ROM, however, checks if it is located in $f00000 (!) and if not, checks if $f00000 contains any valid ROM and jumps there. (a5 contains the return address, as elsewhere in Boot-ROM code.) BUT: Boot-ROM contains much position dependent code, and would have to be totally corrected for the new location. Changing the loader wouldn't be so difficult to load whatever Kick version. This Task would be MUCH easier with some co-operation with Commodore-Amiga (SOURCES!, we NEED SOURCE-CODE!). Another solution would be to let the 1.3 boot normally, and then write a program to load 2.0. There are few problems with this: - RESET disables the chip-RAM. So some FAST is needed. - Would C-A-A-reset work normally??? > Right now I have added an extra 256K ram chip at f80000 to fbffff successfully. > The problem is that the extra decoding address line A18 is tangled in the PAL > equations that perform the write protect function among other things. I need > the info to continue this project. > I don't have any schematics so I can say nothing to this My A1000 (European (PAL) version differs slightly from others I've seen. I't doesn't have separate Kick-RAM board so I can't use any Rejuvenator or such. This project is my only (?) hope to get 2.0. > Will Commodore licence an official 2.0 Kickstart rom image on a floppy ? > > I can see quite a few might want a legal copy. > > (BTW the hardware hack for putting 2.0 in 32-bit ram for the Lucas/Frances > should be as simple as soldering a piece of wire. I can't give any details as > it is still on my drawing board.) > > Thanks in advance. > > K. C. Lee Jarno > > No disclaimer required... -- _____________________________________________________________________________ | // Address: Jarno Rajahalme | EMail: | | //| Servin Maijan tie 12 H 111 | jrajahal@otax.tky.hut.hi | | \\ //-| M I G A 02150 ESPOO | d37686l@kaira.hut.fi | | \X/ | forever!! FINLAND , tel (90) 4682891 | jraja@niksula.hut.fi | -----------------------------------------------------------------------------