### Known Bugs

#### General problems

- There is a general problem with all extra hardware connected to the Amiga which generates Interrupts at random or regular times. An example is my network card (Hydra). If I have my TCP/IP stack running, nearly every installed program will freeze after a short time because the card creates PORTS interrupts (the same type as interrupts created by the keyboard) which cannot correctly replied to by the installed program. This is because as soon as the request has been acknowledged with an rte, the next interrupt occurs. To avoid this problem, the TCP/IP stack must be stopped before starting WHDLoad.
  In the same category are falling USB-stacks (use "AddUSBHardware REMOVE ALL" for Poseidon) and the Voodoo interrupt of Mediator boards (you have to set "VoodooInt = No"). Starting WHDLoad version 16.8 there is a built-in work around for the interrupts created by Mediator boards, therefore no special settings are required.
- If you get errors concerning reading/writing of files check that your hard disks are correctly configured. WHDLoad reads large chunks of data (>1MB) which may easily show up improper configurations although other applications seems to work fine. That means make sure that the setting of MaxTransfer and Mask in HDToolBox on all partitions are correctly set. A safe value (for awkward hardware) is MaxTransfer = 0x0FE00 and Mask = 0x0FFFFFC. This applies especially to cards in the PCMCIA slot and to IDE-CF-card adapters.
  Another reason for problems can be memory allocations. There are configurations which have problems with Reverse memory allocations. In such a case WHDLoad can be forced to not use the Reverse mode by setting the NoMemReverse option.
- If you are using the Picasso96 software you must make sure that the option FakeNativeModes is set to NO (tooltype of the monitor driver). Otherwise there will be graphics errors and maybe crashes.
- There are some rare hardware configurations which don't support the MMU related features of WHDload. The only systems affected are 68030 based. The option MMU/S must not enabled on these systems! If the option is set, WHDLoad will freeze the whole machine. Currently the following hardware is known to cause problems: accelerator boards "Apollo A630", "Apollo 1230", "Elbox 1230" and "Magnum MK2".
- There seems to be problems with RAM expansions via PCMCIA on A1200. WHDLoad may show error requesters like `Dos error #235 (executable not valid) on loading "xxx.slave"`. The reasons seems to be that the memory is incorrectly bound into the system memory lists, because WHDLoad attempt to allocate memory using the flag MEMF_REVERSE and gets an invalid return value (pointer to non existent memory). It's not known if this happens only with specific cards or under specific configurations.

#### Developer related

- The operation of switching between the operation system (OS) and the installed program is not completely reliable. The problem is that most Custom registers and some Cia registers cannot be read and therefore cannot be saved and restored. WHDLoad itself does not change these registers, but when it switches from the installed program to the OS (e.g. to load a file from disk) the OS may change some of these not restorable registers. If the installed program depends on all registers remaining unchanged, this will cause problems. It is known that the OS changes at least cop2lc, bltafwm and bltalwm, and perhaps more. As a workround for this problem there is a possibility to restore the changed registers during the switch sequence. See WHDLTAG_CBSWITCH_SET for more info.