Editing PRX File Format

Structure of the PRX Goes as follows

= PRX File Format Structure =

{| class="wikitable sortable"
|-
! Offset !! Size !! Description !! Notes
|-
| 0x0 || 4 || Magic || ~PSP
|-
| 0x6 || 2 || Compression Type || 0x300-Plain, 0x200-KL4E, 0x100-2RLZ, 0x000-GZIP Little endian u16 & 0xF00
|-
| 0x28 || 4 || Plaintext Size (ELF) || Little endian u32
|-
| 0x2C || 4 || Total Size || Little endian u32
|-
| 0x34 || 4 || Filetype || if ((s32)(header+0x34) >=0) (Determines if user (positive) or kernel (negative) )
|-
| 0xD0 || 4 || Key Tag Type || Little endian u32
|-
| 0x7C || 1 || Encryption Type  ||  0 - internal / 1 - ??? / 2 - supported by multiloader / 3 - Used by vshmain (???) 
|-
|}

= PRX Types & Tags =
Reversed by Linblow

Extracted from the mesg_led_02g kernel module (firmware<code>6.61</code>model <code>02g</code>).

=== PSP header v1 (0/1/8) ===
Use PSP header structure v1.

Primary key size: <code>144</code> bytes.

No secondary key, and no secure ID.

    Type 0: 03000000 (mode: 4  USER_MODULE)
    Type 0: 04000000 (mode: 5)
    Type 0: 05000000 (mode: 6)
    Type 0: 06000000 (mode: 7  PSAR_DEVTOOL)
    Type 0: 08000000 (mode: 9  UMD_GAME_EXEC)
    Type 0: 09000000 (mode: 10 GAMESHARING_EXEC)
    Type 0: 0A000000 (mode: 11 GAMESHARING_EXEC_DEVTOOL)
    Type 0: 0C000000 (mode: 13 DEMO_EXEC)
    Type 0: 0D000000 (mode: 14 APP_MODULE)
    Type 0: 0E000000 (mode: 15 PSAR_RETAIL)
    Type 0: 0F000000 (mode: 16 ME_IMAGE)
    Type 1: 3ACE4DCE (mode: 4  USER_MODULE)
    Type 1: C0CB167C (mode: 9  UMD_GAME_EXEC)
    Type 1: BB67C59F (mode: 10 GAMESHARING_EXEC)
    Type 1: 7F24BDCD (mode: 13 DEMO_EXEC)
    Type 1: 1BC8D12B (mode: 14 APP_MODULE)
    Type 1: 862648D1 (mode: 16 ME_IMAGE)
    Type 8: 02000000 (mode: 3  VSH_MODULE)
    Type 8: 0B000000 (mode: 12 MS_UPDATER)

=== PSP header v2 ===
Use PSP header structure v2.

Primary key size: <code>16</code> bytes.

Secondary key size: <code>16</code> bytes.

Secure ID: type-dependent, <code>16</code> bytes.

==== Type 2/4/6/9 (no secure ID) ====
    Type 2: 457B05F0 (mode: 4  USER_MODULE)
    Type 2: 457B06F0 (mode: 4  USER_MODULE)
    Type 2: 457B08F0 (mode: 4  USER_MODULE)
    Type 2: 457B0AF0 (mode: 4  USER_MODULE)
    Type 2: 457B0BF0 (mode: 4  USER_MODULE)
    Type 2: 457B0CF0 (mode: 4  USER_MODULE)
    Type 2: 457B10F0 (mode: 4  USER_MODULE)
    Type 2: 76202403 (mode: 4  USER_MODULE)
    Type 2: 628910F0 (mode: 5)
    Type 2: 8B9B10F0 (mode: 6)
    Type 2: 5A5C10F0 (mode: 7  PSAR_DEVTOOL)
    Type 2: E42C2303 (mode: 7  PSAR_DEVTOOL)
    Type 2: 8004FD03 (mode: 9  UMD_GAME_EXEC)
    Type 2: D91605F0 (mode: 9  UMD_GAME_EXEC)
    Type 2: D91606F0 (mode: 9  UMD_GAME_EXEC)
    Type 2: D9160AF0 (mode: 9  UMD_GAME_EXEC)
    Type 2: D9160BF0 (mode: 9  UMD_GAME_EXEC)
    Type 2: D91610F0 (mode: 9  UMD_GAME_EXEC)
    Type 2: 0A35EA03 (mode: 10 GAMESHARING_EXEC)
    Type 2: 7B0505F0 (mode: 10 GAMESHARING_EXEC)
    Type 2: 7B0506F0 (mode: 10 GAMESHARING_EXEC)
    Type 2: 7B0508F0 (mode: 10 GAMESHARING_EXEC)
    Type 2: 7B0510F0 (mode: 10 GAMESHARING_EXEC)
    Type 2: EFD210F0 (mode: 11 GAMESHARING_EXEC_DEVTOOL)
    Type 2: D67B3303 (mode: 13 DEMO_EXEC)
    Type 2: D66DF703 (mode: 14 APP_MODULE)
    Type 2: 63BAB403 (mode: 15 PSAR_RETAIL)
    Type 2: D82310F0 (mode: 15 PSAR_RETAIL)
    Type 2: 1B11FD03 (mode: 16 ME_IMAGE)
    Type 2: D13B05F0 (mode: 16 ME_IMAGE)
    Type 2: D13B06F0 (mode: 16 ME_IMAGE)
    Type 2: D13B08F0 (mode: 16 ME_IMAGE)
    Type 2: D13B10F0 (mode: 16 ME_IMAGE)
    Type 2: 3C2A08F0 (mode: 22)
    Type 2: 3C2A10F0 (mode: 22)
    Type 4: ADF310F0 (mode: 13 DEMO_EXEC)
    Type 4: ADF305F0 (mode: 13 DEMO_EXEC)
    Type 4: ADF306F0 (mode: 13 DEMO_EXEC)
    Type 4: ADF308F0 (mode: 13 DEMO_EXEC)
    Type 4: 279D05F0 (mode: 14 APP_MODULE)
    Type 4: 279D06F0 (mode: 14 APP_MODULE)
    Type 4: 279D08F0 (mode: 14 APP_MODULE)
    Type 4: 279D10F0 (mode: 14 APP_MODULE)
    Type 6: 457B80F0 (mode: 4  USER_MODULE)
    Type 6: 457B8AF0 (mode: 4  USER_MODULE)
    Type 9: 380290F0 (mode: 3  VSH_MODULE)
    Type 9: 380291F0 (mode: 3  VSH_MODULE)
    Type 9: 457B90F0 (mode: 4  USER_MODULE)
    Type 9: 457B91F0 (mode: 4  USER_MODULE)
    Type 9: 0B2B91F0 (mode: 8)

==== Type 3/5/7/10 (optional secure ID) ====
    Type 3: 89742B04 (mode: 18 MS_DNAS_DRMBB)
    Type 3: E92408F0 (mode: 18 MS_DNAS_DRMBB)
    Type 3: E92410F0 (mode: 18 MS_DNAS_DRMBB)
    Type 3: 692808F0 (mode: 19 MS_DNAS_DRMBB_DEVTOOL)
    Type 3: 692810F0 (mode: 19 MS_DNAS_DRMBB_DEVTOOL)
    Type 3: F5F12304 (mode: 19 MS_DNAS_DRMBB_DEVTOOL)
    Type 5: 0DAA06F0 (mode: 20 POPS_EXEC)
    Type 5: 0DAA10F0 (mode: 20 POPS_EXEC)
    Type 5: E1ED06F0 (mode: 21)
    Type 5: E1ED10F0 (mode: 21)
    Type 5: 407810F0 (mode: 23)
    Type 5: 2E5E10F0 (mode: 25 MS_BOOT_PATCH)