From a22d671f42686afe9434f44ae498912abe27b2ed Mon Sep 17 00:00:00 2001
From: Alice Ziuziakowska <a.ziuziakowska@lowrisc.org>
Date: Mon, 1 Jun 2026 13:41:42 +0100
Subject: [PATCH 1/2] app: fix payload size in `bootstrap` command

This was erroneously doubling the file size instead of rounding it up
to the nearest multiple of the flash page size.

Signed-off-by: Alice Ziuziakowska <a.ziuziakowska@lowrisc.org>
---
 app/commands.hh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/commands.hh b/app/commands.hh
index 7e8028e..75d77b3 100644
--- a/app/commands.hh
+++ b/app/commands.hh
@@ -218,7 +218,7 @@ struct LoadFile : public Commands<T> {
       std::println("File is empty");
       return 0;
     }
-    auto size = file_size + (file_size - file_size % flash::PageSize);
+    auto size = (file_size + flash::PageSize - 1) & ~(flash::PageSize - 1);
     std::vector<uint8_t> buffer(size, 0xff);
     if (!file.read(reinterpret_cast<char*>(buffer.data()), file_size)) {
       std::println("Error reading the file.");

From bbfcee3370f238a695f0622eb25f80acbdc99e3d Mon Sep 17 00:00:00 2001
From: Alice Ziuziakowska <a.ziuziakowska@lowrisc.org>
Date: Mon, 1 Jun 2026 13:43:33 +0100
Subject: [PATCH 2/2] flash: allow page program to program less than a whole
 page at a time

Signed-off-by: Alice Ziuziakowska <a.ziuziakowska@lowrisc.org>
---
 lib/flash/flash.hh | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/flash/flash.hh b/lib/flash/flash.hh
index 51aee5e..8693599 100644
--- a/lib/flash/flash.hh
+++ b/lib/flash/flash.hh
@@ -264,16 +264,17 @@ class Generic {
       op = Opcode::PageProgram4b;
     }
 
-    std::array<uint8_t, 256 + 1 + ADDR_SIZE> cmd = {op};
+    auto total_size = 1 + ADDR_SIZE + data.size();
+    std::array<uint8_t, 1 + ADDR_SIZE + flash::PageSize> cmd = {op};
     for (size_t i = 0; i < ADDR_SIZE; ++i) {
       // This calculates the correct shift (24, 16, 8, 0 for 4-byte; 16, 8, 0 for 3-byte)
       cmd[1 + i] = static_cast<uint8_t>(address >> (8 * (ADDR_SIZE - 1 - i)));
     }
 
-    auto slice = std::span<uint8_t>(cmd).last<256>();
+    auto payload = std::span<uint8_t>(cmd).last<flash::PageSize>();
+    std::ranges::copy(data, payload.begin());
 
-    std::ranges::copy(data, slice.begin());
-    TRY_OPT(spih.transfer(cmd, std::span<uint8_t>()));
+    TRY_OPT(spih.transfer(std::span<uint8_t>(cmd).subspan(0, total_size), std::span<uint8_t>()));
     return true;
   }