Xbox 360:GPU Retrofit

Some GPUs can be retrofitted onto earlier boards. This page contains instructions for what changes need to be done in order for the retrofit to work.

Zephyr_B/C
Both variants of the Jasper 65nm GPU can be retrofitted onto a Zephyr_B/C motherboard. (Demo Video)

Guide By: Octal450

Instructions
 GPU Table 

 Install GPU 
 * Replace 80nm U4D1 with 65nm

 Set VID 1.075V 
 * Remove 0 ohm R8B9
 * Remove 0 ohm R8B10

 Set FSB/PCIe/Memory Calibration 
 * FSB:
 * Remove 4.87K ohm R5R3
 * Install 40.2 ohm as pullup to nearby V_GPUCORE
 * You can either use a wire to the capacitor as shown, or scrape to expose V_GPUCORE voltage plane
 * Fsbcal65.pngFsbcal65b.png


 * PCIe:
 * Remove 1.47K ohm R4R3
 * Remove 562 ohm R5D1
 * Replace 2K ohm R5D2 with 49.9 ohm
 * Memory:
 * Replace 40.2 ohm R4R8 with 240 ohm
 * Replace 40.2 ohm R4T1 with 240 ohm

 Tie V_GPUPCIE to V_GPUCORE 
 * Remove IC U5C1
 * Install jumper as shown to tie V_GPUPCIE to V_GPUCORE
 * Be careful not to short to any nearby components or pads
 * Strongly recommended to cover jumper with PCB mask
 * Vpcietie65.png

 Modify Firmware 
 * Use J-Runner with Extras to dump the nand
 * Change the type to Jasper 16MB, then RGH the console to get the CPU key
 * Set the required XeBuild options and build the image
 * Open the SMC Config Editor from the Nand menu, and update the thermal targets from the table above
 * Write the nand to the console

Falcon
Both variants of the Jasper 65nm GPU can be retrofitted onto a Falcon motherboard. (Demo Video)

Guide By: Octal450

Instructions
 GPU Table 

 Install GPU 
 * Replace 80nm U4D1 with 65nm

 Set VID 1.075V 
 * Remove 0 ohm R8B9
 * Remove 0 ohm R8B10

 Set FSB/PCIe/Memory Calibration 
 * FSB:
 * Install 40.2 ohm R4R9
 * Remove 4.87K ohm R5R3
 * PCIe:
 * Remove 1.47K ohm R4R3
 * Remove 562 ohm R5D1
 * Replace 2K ohm R5D2 with 49.9 ohm
 * Memory:
 * Replace 40.2 ohm R4R8 with 240 ohm
 * Replace 40.2 ohm R4T1 with 240 ohm

 Tie V_GPUPCIE to V_GPUCORE 
 * Remove 0 ohm R4C31
 * Install 0 ohm R4P13
 * Install 0 ohm R4P14
 * Remove IC U5C1

 Modify Firmware 
 * Use J-Runner with Extras to dump the nand
 * Change the type to Jasper 16MB, then RGH the console to get the CPU key
 * Set the required XeBuild options and build the image
 * Open the SMC Config Editor from the Nand menu, and update the thermal targets from the table above
 * Write the nand to the console

Jasper V1
The Kronos GPU can be retrofitted onto a Jasper V1 motherboard. (Demo video)

Guide By: Octal450

Instructions
 GPU Table 

 Install GPU 
 * Replace Zeus U4D1 with Kronos

 Modify Firmware (Optional)
 * This step is optional, Zeus targets 71C/73C, there is no harm by running the chip a few degrees cooler
 * Use J-Runner with Extras to dump the nand
 * Open the SMC Config Editor from the Nand menu, and update the thermal targets from the table above
 * Write the nand to the console