Thank you for providing the code and identifying the CWE-787 vulnerability. I'll generate five possible patches to address this out-of-bounds write vulnerability in the DecodeBase64Block function. Here are the patches:

Patch 1: Add bounds checking before writing to ascii array
```c
static inline void DecodeBase64Block(uint8_t ascii[ASCII_BLOCK], uint8_t b64[B64_BLOCK])
{
    if (ASCII_BLOCK >= 1) {
        ascii[0] = (uint8_t) (b64[0] << 2) | (b64[1] >> 4);
    }
    if (ASCII_BLOCK >= 2) {
        ascii[1] = (uint8_t) (b64[1] << 4) | (b64[2] >> 2);
    }
    if (ASCII_BLOCK >= 3) {
        ascii[2] = (uint8_t) (b64[2] << 6) | (b64[3]);
    }
}
```

Patch 2: Use a safer function with built-in bounds checking
```c
#include <string.h>

static inline void DecodeBase64Block(uint8_t ascii[ASCII_BLOCK], uint8_t b64[B64_BLOCK])
{
    uint8_t temp[3];
    temp[0] = (uint8_t) (b64[0] << 2) | (b64[1] >> 4);
    temp[1] = (uint8_t) (b64[1] << 4) | (b64[2] >> 2);
    temp[2] = (uint8_t) (b64[2] << 6) | (b64[3]);
    memcpy(ascii, temp, ASCII_BLOCK < 3 ? ASCII_BLOCK : 3);
}
```

Patch 3: Pass the size of ascii array as a parameter
```c
static inline void DecodeBase64Block(uint8_t *ascii, size_t ascii_size, uint8_t b64[B64_BLOCK])
{
    if (ascii_size >= 1) {
        ascii[0] = (uint8_t) (b64[0] << 2) | (b64[1] >> 4);
    }
    if (ascii_size >= 2) {
        ascii[1] = (uint8_t) (b64[1] << 4) | (b64[2] >> 2);
    }
    if (ascii_size >= 3) {
        ascii[2] = (uint8_t) (b64[2] << 6) | (b64[3]);
    }
}
```

Patch 4: Use a macro to ensure ASCII_BLOCK is at least 3
```c
#define MIN_ASCII_BLOCK 3
#if ASCII_BLOCK < MIN_ASCII_BLOCK
#error "ASCII_BLOCK must be at least 3"
#endif

static inline void DecodeBase64Block(uint8_t ascii[ASCII_BLOCK], uint8_t b64[B64_BLOCK])
{
    ascii[0] = (uint8_t) (b64[0] << 2) | (b64[1] >> 4);
    ascii[1] = (uint8_t) (b64[1] << 4) | (b64[2] >> 2);
    ascii[2] = (uint8_t) (b64[2] << 6) | (b64[3]);
}
```

Patch 5: Use a struct to ensure proper sizing
```c
struct AsciiBlock {
    uint8_t data[3];
};

static inline void DecodeBase64Block(struct AsciiBlock *ascii, uint8_t b64[B64_BLOCK])
{
    ascii->data[0] = (uint8_t) (b64[0] << 2) | (b64[1] >> 4);
    ascii->data[1] = (uint8_t) (b64[1] << 4) | (b64[2] >> 2);
    ascii->data[2] = (uint8_t) (b64[2] << 6) | (b64[3]);
}
```

Each of these patches aims to prevent the out-of-bounds write by either adding checks, using safer functions, or ensuring proper sizing. The choice of patch depends on the specific requirements and constraints of your project.